Game crash while retiring dungeon

[tim-oleksii]

I launched the game from bash to observe possible misbehaviour. A terminal contained following information

[tim-oleksii@fermion KeeperRL]$ ./keeper_linux.sh 
[S_API] SteamAPI_Init(): Loaded '/home/tim-oleksii/.local/share/Steam/linux64/steamclient.so' OK.
[S_API FAIL] SteamAPI_Init() failed; no appID found.
Either launch the game from Steam, or put the file steam_appid.txt containing the correct appID in your game folder.
Unable to connect with the Steam client.
[S_API FAIL] Tried to access Steam interface SteamUtils010 before SteamAPI_Init succeeded.
[S_API FAIL] Tried to access Steam interface SteamInput006 before SteamAPI_Init succeeded.
FATAL level.cpp:56 : !model->serializationLocked is false. 
./keeper_linux.sh: line 3: 92901 Segmentation fault      (core dumped) ./keeper