Eh, fair, but this is being submitted as his work.
Yes, and so it is.
If we want to get legal it falls under Fair Use.
Picture 1 you provided is an asset from World's Dawn or what have you (idk anything about that game).
Picture 2 does share, albeit little, resemblance to Picture 1 but it's context is unique to TEW as Picture 1's own context is unique to World's Dawn.
And also good catch and comparison; probably a superpower that comes from being an artist?
Ninjaman2 brings up good really good points to core gameplay <- which actually reminds me of CoC's Prison content.
Whether this game is intended to be an expanded redesign of that style or not, it seems that there may be an audience for a fuller game with that style. It seems if you're able to include game assets that satisfy TheSubject, you may end up with a real money maker.