diff --git a/README.md b/README.md
index c1135f1..69d12ca 100644
--- a/README.md
+++ b/README.md
@@ -28,7 +28,7 @@ Running tests in hypothetical JavaScript engine "X":
 
 ```
 cd test262;
-test262-harness --hostType=X --hostPath=`which X` test/**/*.js
+test262-harness --host-type=X --host-path=`which X` test/**/*.js
 ```
 
 
@@ -40,24 +40,26 @@ test262-harness --hostType=X --hostPath=`which X` test/**/*.js
 | -- | -- | -- | -- |
 | `-h`, `--help` | Show help & examples | n/a | n/a |
 | `-v`, `--version` | Print the current version of test262-harness | n/a | n/a |
-| `--hostType` | Type of host to run tests in. See [eshost's supported hosts](https://github.com/bterlson/eshost#supported-hosts) for available options. | No | `node`
-| `--hostPath` | Path to the host executable. | Yes, if `hostType` is specified | `process.execPath` 
-| `--hostArgs` | Any additional arguments to pass to the host when invoking it (eg. `--harmony`, `--es6all`, etc). | No | n/a |
+| `--host-type` | Type of host to run tests in. See [eshost's supported hosts](https://github.com/bterlson/eshost#supported-hosts) for available options. | No | `node`
+| `--host-path` | Path to the host executable. | Yes, if `host-type` is specified | `process.execPath`
+| `--host-args` | Any additional arguments to pass to the host when invoking it (eg. `--harmony`, `--es6all`, etc). | No | n/a |
 | `-t`, `--threads` | Run this many tests in parallel. Note that the browser runners don't work great with t > 1. | No | 1 |
 | `-r`, `--reporter` | Format of data written to standard output. Currently either `json` or `simple`. | No |  `simple` |
-| `--features` | Comma-separated list of [`features`](https://github.com/tc39/test262/blob/master/features.txt) to filter for. Example: `--features="BigInt,Atomics"`. | No | n/a |
+| `--features` (deprecated) | Comma-separated list of [`features`](https://github.com/tc39/test262/blob/master/features.txt) to filter for. Example: `--features="BigInt,Atomics"`. | No | n/a |
+| `--features-include` | Comma-separated list of [`features`](https://github.com/tc39/test262/blob/master/features.txt) to filter for _inclusion_. Example: `--features-include="BigInt,Atomics"` would run only tests that include the features `BigInt` and `Atomics` | No | n/a |
+| `--features-exclude` | Comma-separated list of [`features`](https://github.com/tc39/test262/blob/master/features.txt) to filter for _exclusion_. Example: `--features-exclude="BigInt,Atomics"` would run only tests that do not include the features `BigInt` and `Atomics`. **NOTE** exclusions are resolved _after_ inclusions. | No | n/a |
 | `--reporter-keys` | Comma-separated list of keys to include in output of `json` reporter. | No | n/a |
-| `--test262Dir` | Root test262 directory and is used to locate the includes directory. | No | Relative to test files |
-| `--includesDir` | Includes directory. | No | Inferred from `test262Dir` or else detected by walking upward from the first test found. |
-| `--tempDir` | Directory that `eshost` will create its temp files in (does not affect location of files created by `--saveCompiledTests` and `--saveOnlyFailed` | No | OS Temp Dir |
+| `--test262-dir` | Root test262 directory and is used to locate the includes directory. | No | Relative to test files |
+| `--includes-dir` | Includes directory. | No | Inferred from `test262-dir` or else detected by walking upward from the first test found. |
+| `--tempDir` | Directory that `eshost` will create its temp files in (does not affect location of files created by `--save-compiled-tests` and `--save-only-failed` | No | OS Temp Dir |
 | `--prelude` | Path to a file to include before every test (useful for testing polyfills for example); supports multiple `--prelude` parameters | No | n/a |
 | `--timeout` | Set a custom test timeout in milliseconds | No | `10000` |
 | `--transformer` | Path to module which exports a code transformer function | No | n/a |
 | `--preprocessor` | Path to module which exports a map function that operates on each Test262Test object before it executed. | No | n/a |
-| `--acceptVersion` | Execute tests from a version of Test262 that differs from the versions supported by this utility. This may cause the utility to report invalid test results. | No | Inferred from `test262Dir/package.json` |
-| `--saveCompiledTests` | Write the compiled version of `path/to/test.js` as `path/to/test.js.<hostType>.<default\|strict>.<pass\|fail>` so that it can be easily re-run under that host. Run `test262-harness --help` for examples. | No | n/a 
-| `--saveOnlyFailed` | Only save the compiled version of the test if it failed, to help easily repro failed tests (implies `--saveCompiledTests`). | No | n/a 
-| `--errorForFailures` | Return a non-zero exit code if one or more tests fail. | No | n/a
+| `--accept-version` | Execute tests from a version of Test262 that differs from the versions supported by this utility. This may cause the utility to report invalid test results. | No | Inferred from `test262Dir/package.json` |
+| `--save-compiled-tests` | Write the compiled version of `path/to/test.js` as `path/to/test.js.<host-type>.<default\|strict>.<pass\|fail>` so that it can be easily re-run under that host. Run `test262-harness --help` for examples. | No | n/a
+| `--save-only-failed` | Only save the compiled version of the test if it failed, to help easily repro failed tests (implies `--save-compiled-tests`). | No | n/a
+| `--error-for-failures` | Return a non-zero exit code if one or more tests fail. | No | n/a
 
 
 ### Preprocessor
diff --git a/bin/run.js b/bin/run.js
index d83806a..d9c46d2 100755
--- a/bin/run.js
+++ b/bin/run.js
@@ -75,7 +75,8 @@ if (argv.prelude) {
 // If using default hostType, hostPath defaults to the current node executable location.
 let hostType;
 let hostPath;
-let features;
+let featuresInclude;
+let featuresExclude;
 
 if (argv.hostType) {
   hostType = argv.hostType;
@@ -119,8 +120,12 @@ if (argv.preprocessor) {
   preprocessor = require(preprocessorPath);
 }
 
-if (argv.features) {
-  features = argv.features.split(',').map(feature => feature.trim());
+if (argv.features || argv.featuresInclude) {
+  featuresInclude = (argv.features || argv.featuresInclude).split(',').map(feature => feature.trim());
+}
+
+if (argv.featuresExclude) {
+  featuresExclude = argv.featuresExclude.split(',').map(feature => feature.trim());
 }
 
 // Show help if no arguments provided
@@ -141,6 +146,7 @@ if (!test262Dir) {
 reporterOpts.test262Dir = test262Dir;
 
 const remove = path.relative(process.cwd(), test262Dir);
+
 argv._ = argv._.map(p => path.relative(remove, p));
 
 let test262Version;
@@ -160,7 +166,7 @@ if (!acceptVersion) {
 
 const stream = new TestStream(test262Dir, includesDir, acceptVersion, argv._);
 
-let tests = stream.pipe(filter(hasFeatures)).pipe(map(insertPrelude));
+let tests = stream.pipe(filter(filterByFeatureInclude)).pipe(filter(filterByFeatureExclude)).pipe(map(insertPrelude));
 
 if (preprocessor) {
   tests = tests.pipe(filter(preprocessor));
@@ -207,9 +213,16 @@ function insertPrelude(test) {
   return test;
 }
 
-function hasFeatures(test) {
-  if (!features) {
+function filterByFeatureInclude(test) {
+  if (!featuresInclude) {
+    return true;
+  }
+  return featuresInclude.filter(feature => (test.attrs.features || []).includes(feature)).length > 0;
+}
+
+function filterByFeatureExclude(test) {
+  if (!featuresExclude) {
     return true;
   }
-  return features.filter(feature => (test.attrs.features || []).includes(feature)).length > 0;
+  return featuresExclude.filter(feature => !(test.attrs.features || []).includes(feature)).length > 0;
 }
diff --git a/lib/cli.js b/lib/cli.js
index a232682..bc4f685 100644
--- a/lib/cli.js
+++ b/lib/cli.js
@@ -3,12 +3,12 @@ const yargs = require('yargs');
 const yargv = yargs
   .strict()
   .usage('Usage: test262-harness [options] <test-file-glob>')
-  .describe('hostType', `eshost host type (${supportedHosts.join(", ")}, etc.)`)
-  .describe('hostPath', 'path to eshost host binary')
-  .describe('hostArgs', 'command-line arguments to pass to eshost host')
-  .describe('test262Dir', 'test262 root directory')
-  .describe('includesDir', 'directory where helper files are found')
-  .describe('tempDir', 'directory that eshost will create its temp files in (does not affect location of files created by --saveCompiledTests and --saveOnlyFailed')
+  .describe('host-type', `eshost host type (${supportedHosts.join(", ")}, etc.)`)
+  .describe('host-path', 'path to eshost host binary')
+  .describe('host-args', 'command-line arguments to pass to eshost host')
+  .describe('test262-dir', 'test262 root directory')
+  .describe('includes-dir', 'directory where helper files are found')
+  .describe('temp-dir', 'directory that eshost will create its temp files in (does not affect location of files created by --saveCompiledTests and --saveOnlyFailed')
   .describe('threads', 'number of threads to use')
   .describe('prelude', 'content to include above each test; supports multiple --prelude parameters')
   .describe('version', 'print version of test262-harness')
@@ -16,6 +16,12 @@ const yargv = yargs
   .describe('features', 'comma-separated list of features to filter for')
   .nargs('features', 1)
   .alias('features', 'f')
+  .describe('features-exclude', 'comma-separated list of features to filter for exclusion')
+  .nargs('features-exclude', 1)
+  .alias('features-exclude', 'fe')
+  .describe('features-include', 'comma-separated list of features to filter for inclusion')
+  .nargs('features-include', 1)
+  .alias('features-include', 'fi')
   .describe('transformer', 'path to module which exports a code transformer function')
   .describe('preprocessor', 'path to module which exports a map function that operates on each Test262Test object before it executed')
   .nargs('prelude', 1)
@@ -32,16 +38,16 @@ const yargv = yargs
   .alias('help', 'h')
   .describe('timeout', 'test timeout (in ms, default 10000)')
   .nargs('timeout', 1)
-  .describe('acceptVersion', 'override for supported Test262 version')
-  .boolean('saveCompiledTests')
-  .describe('saveCompiledTests', 'Write the compiled version of path/to/test.js as path/to/test.js.<hostType>.<default|strict>.<pass|fail> so that it can be easily re-run under that host')
-  .boolean('saveOnlyFailed')
-  .describe('saveOnlyFailed', 'Only save the compiled version of the test if it failed, to help easily repro failed tests (implies --saveCompiledTests)')
-  .describe('errorForFailures', 'Return a non-zero exit code if one or more tests fail')
+  .describe('accept-version', 'override for supported Test262 version')
+  .boolean('save-compiled-tests')
+  .describe('save-compiled-tests', 'Write the compiled version of path/to/test.js as path/to/test.js.<host-type>.<default|strict>.<pass|fail> so that it can be easily re-run under that host')
+  .boolean('save-only-failed')
+  .describe('save-only-failed', 'Only save the compiled version of the test if it failed, to help easily repro failed tests (implies --saveCompiledTests)')
+  .describe('error-for-failures', 'Return a non-zero exit code if one or more tests fail')
   .example('test262-harness path/to/test.js')
-  .example('test262-harness --hostType ch --hostPath path/to/host path/to/test262/test/folder/**/*.js')
-  .example('test262-harness --hostType ch --hostPath path/to/host --saveCompiledTests path/to/test262/test/folder/**/*.js')
-  .example('test262-harness --hostType ch --hostPath path/to/host --saveOnlyFailed path/to/test262/test/folder/**/*.js')
+  .example('test262-harness --host-type ch --host-Path path/to/host path/to/test262/test/folder/**/*.js')
+  .example('test262-harness --host-type ch --host-Path path/to/host --save-compiled-tests path/to/test262/test/folder/**/*.js')
+  .example('test262-harness --host-type ch --host-Path path/to/host --save-only-failed path/to/test262/test/folder/**/*.js')
   .fail((msg, err) => {
     if (err) {
       console.error(err.stack);
diff --git a/test/collateral/harness/.gitkeep b/test/collateral/harness/.gitkeep
deleted file mode 100644
index e69de29..0000000
diff --git a/test/collateral/harness/assert.js b/test/collateral/harness/assert.js
new file mode 100644
index 0000000..5fbc122
--- /dev/null
+++ b/test/collateral/harness/assert.js
@@ -0,0 +1,95 @@
+// Copyright (C) 2017 Ecma International.  All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: |
+    Collection of assertion functions used throughout test262
+---*/
+
+function assert(mustBeTrue, message) {
+  if (mustBeTrue === true) {
+    return;
+  }
+
+  if (message === undefined) {
+    message = 'Expected true but got ' + String(mustBeTrue);
+  }
+  $ERROR(message);
+}
+
+assert._isSameValue = function (a, b) {
+  if (a === b) {
+    // Handle +/-0 vs. -/+0
+    return a !== 0 || 1 / a === 1 / b;
+  }
+
+  // Handle NaN vs. NaN
+  return a !== a && b !== b;
+};
+
+assert.sameValue = function (actual, expected, message) {
+  if (assert._isSameValue(actual, expected)) {
+    return;
+  }
+
+  if (message === undefined) {
+    message = '';
+  } else {
+    message += ' ';
+  }
+
+  message += 'Expected SameValue(«' + String(actual) + '», «' + String(expected) + '») to be true';
+
+  $ERROR(message);
+};
+
+assert.notSameValue = function (actual, unexpected, message) {
+  if (!assert._isSameValue(actual, unexpected)) {
+    return;
+  }
+
+  if (message === undefined) {
+    message = '';
+  } else {
+    message += ' ';
+  }
+
+  message += 'Expected SameValue(«' + String(actual) + '», «' + String(unexpected) + '») to be false';
+
+  $ERROR(message);
+};
+
+assert.throws = function (expectedErrorConstructor, func, message) {
+  if (typeof func !== "function") {
+    $ERROR('assert.throws requires two arguments: the error constructor ' +
+      'and a function to run');
+    return;
+  }
+  if (message === undefined) {
+    message = '';
+  } else {
+    message += ' ';
+  }
+
+  try {
+    func();
+  } catch (thrown) {
+    if (typeof thrown !== 'object' || thrown === null) {
+      message += 'Thrown value was not an object!';
+      $ERROR(message);
+    } else if (thrown.constructor !== expectedErrorConstructor) {
+      message += 'Expected a ' + expectedErrorConstructor.name + ' but got a ' + thrown.constructor.name;
+      $ERROR(message);
+    }
+    return;
+  }
+
+  message += 'Expected a ' + expectedErrorConstructor.name + ' to be thrown but no exception was thrown at all';
+  $ERROR(message);
+};
+
+assert.throws.early = function(err, code) {
+  var wrappedCode = 'function wrapperFn() { ' + code + ' }';
+  var ieval = eval;
+
+  assert.throws(err, function() { Function(wrappedCode); }, 'Function: ' + code);
+};
diff --git a/test/collateral/harness/doneprintHandle.js b/test/collateral/harness/doneprintHandle.js
new file mode 100644
index 0000000..a6ea799
--- /dev/null
+++ b/test/collateral/harness/doneprintHandle.js
@@ -0,0 +1,22 @@
+// Copyright (C) 2017 Ecma International.  All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: |
+
+---*/
+
+function __consolePrintHandle__(msg) {
+  print(msg);
+}
+
+function $DONE(error) {
+  if (error) {
+    if(typeof error === 'object' && error !== null && 'name' in error) {
+      __consolePrintHandle__('Test262:AsyncTestFailure:' + error.name + ': ' + error.message);
+    } else {
+      __consolePrintHandle__('Test262:AsyncTestFailure:Test262Error: ' + error);
+    }
+  } else {
+    __consolePrintHandle__('Test262:AsyncTestComplete');
+  }
+}
diff --git a/test/collateral/harness/sta.js b/test/collateral/harness/sta.js
new file mode 100644
index 0000000..341c21e
--- /dev/null
+++ b/test/collateral/harness/sta.js
@@ -0,0 +1,23 @@
+// Copyright (c) 2012 Ecma International.  All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: |
+    Provides both:
+
+    - An error class to avoid false positives when testing for thrown exceptions
+    - A function to explicitly throw an exception using the Test262Error class
+---*/
+
+
+function Test262Error(message) {
+  this.message = message || "";
+}
+
+Test262Error.prototype.toString = function () {
+  return "Test262Error: " + this.message;
+};
+
+var $ERROR;
+$ERROR = function $ERROR(message) {
+  throw new Test262Error(message);
+};
diff --git a/test/collateral/test/async.js b/test/collateral/test/async.js
index b0f1d0c..ba06fd3 100644
--- a/test/collateral/test/async.js
+++ b/test/collateral/test/async.js
@@ -2,6 +2,7 @@
 description: Async test
 expected:
   pass: true
+features: [A]
 flags: [async]
 ---*/
 
diff --git a/test/collateral/test/asyncNegative.js b/test/collateral/test/asyncNegative.js
index bd884a7..b1d2c79 100644
--- a/test/collateral/test/asyncNegative.js
+++ b/test/collateral/test/asyncNegative.js
@@ -5,6 +5,7 @@ negative:
   type: RangeError
 expected:
   pass: true
+features: [A,B]
 flags: [async]
 ---*/
 
diff --git a/test/collateral/test/bothStrict.js b/test/collateral/test/bothStrict.js
index f069b24..8140cef 100644
--- a/test/collateral/test/bothStrict.js
+++ b/test/collateral/test/bothStrict.js
@@ -7,6 +7,7 @@ negative:
   type: ReferenceError
 expected:
   pass: true
+features: [A]
 ---*/
 var strict;
 try { x = 1; strict = false;} catch(e) { strict = true }
diff --git a/test/collateral/test/negativeMessage.js b/test/collateral/test/negativeMessage.js
index 9c60658..df188c5 100644
--- a/test/collateral/test/negativeMessage.js
+++ b/test/collateral/test/negativeMessage.js
@@ -3,4 +3,5 @@ description: Should report the expected error indicated by the "negative" frontm
 negative: ExpectedError
 expected:
   pass: false
+features: [B]
 ---*/
diff --git a/test/test.js b/test/test.js
index 1bfe6e3..8d36a61 100644
--- a/test/test.js
+++ b/test/test.js
@@ -133,6 +133,42 @@ const tests = [
     ],
     { exitCode: 1 },
   ],
+  [
+    [
+      '--features-include=A',
+      'collateral/test/**/*.js',
+    ],
+    { cwd: 'test', recordsCount: 6 },
+  ],
+  [
+    [
+      '--features-exclude=B',
+      'collateral/test/**/*.js',
+    ],
+    { cwd: 'test', recordsCount: 14 },
+  ],
+  [
+    [
+      '--features-include=A,B',
+      'collateral/test/**/*.js',
+    ],
+    { cwd: 'test', recordsCount: 8 },
+  ],
+  [
+    [
+      '--features-exclude=A,B',
+      'collateral/test/**/*.js',
+    ],
+    { cwd: 'test', recordsCount: 16 },
+  ],
+  [
+    [
+      '--features-include=A',
+      '--features-exclude=B',
+      'collateral/test/**/*.js',
+    ],
+    { cwd: 'test', recordsCount: 4 },
+  ],
 ].reduce((accum, a) => {
   let b = a.slice();
 
@@ -167,56 +203,63 @@ function validate({ args, records, exitCode, options }) {
   });
 
   if (options.reporter === 'json') {
-    records.forEach(record => {
-      const prelude = options && options.prelude;
-      const description = prelude ?
-        `${record.attrs.description} with prelude` :
-        record.attrs.description;
+    if (options.recordsCount) {
+      tap.test('--features-include/exclude', assert => {
+        assert.equal(records.length, options.recordsCount, 'records.length matches expected records count');
+        assert.end();
+      });
+    } else {
+      records.forEach(record => {
+        const prelude = options && options.prelude;
+        const description = prelude ?
+          `${record.attrs.description} with prelude` :
+          record.attrs.description;
 
-      tap.test(description, assert => {
+        tap.test(description, assert => {
 
-        if (typeof record.scenario !== 'undefined') {
-          if (record.contents.startsWith('"use strict"')) {
-            assert.equal(record.scenario, 'strict mode');
-          } else {
-            assert.equal(record.scenario, 'default');
+          if (typeof record.scenario !== 'undefined') {
+            if (record.contents.startsWith('"use strict"')) {
+              assert.equal(record.scenario, 'strict mode');
+            } else {
+              assert.equal(record.scenario, 'default');
+            }
           }
-        }
 
-        assert.notEqual(record.attrs.expected, undefined,
-                        'Test has an "expected" frontmatter');
+          assert.notEqual(record.attrs.expected, undefined,
+                          'Test has an "expected" frontmatter');
 
-        if (!record.attrs.expected) {
-          // can't do anything else
-          assert.end();
-          return;
-        }
+          if (!record.attrs.expected) {
+            // can't do anything else
+            assert.end();
+            return;
+          }
 
-        assert.equal(record.result.pass, record.attrs.expected.pass,
-                      'Test passes or fails as expected');
+          assert.equal(record.result.pass, record.attrs.expected.pass,
+                        'Test passes or fails as expected');
 
-        if (record.attrs.expected.message) {
-          assert.equal(record.result.message, record.attrs.expected.message,
-                      'Test fails with appropriate message');
-        }
+          if (record.attrs.expected.message) {
+            assert.equal(record.result.message, record.attrs.expected.message,
+                        'Test fails with appropriate message');
+          }
 
-        if (prelude) {
-          assert.ok(record.rawResult.stdout.includes('prelude a!'),
-                    'Has prelude-a content');
+          if (prelude) {
+            assert.ok(record.rawResult.stdout.includes('prelude a!'),
+                      'Has prelude-a content');
 
-          assert.ok(record.rawResult.stdout.includes('prelude b!'),
-                    'Has prelude-b content');
-        }
+            assert.ok(record.rawResult.stdout.includes('prelude b!'),
+                      'Has prelude-b content');
+          }
 
-        if (options.noRawResult) {
-          assert.equal(record.rawResult, undefined);
-        } else {
-          assert.equal(typeof record.rawResult, 'object');
-        }
+          if (options.noRawResult) {
+            assert.equal(record.rawResult, undefined);
+          } else {
+            assert.equal(typeof record.rawResult, 'object');
+          }
 
-        assert.end();
+          assert.end();
+        });
       });
-    });
+    }
   }
 
   if (options.reporter === 'simple') {