Thanks for trying the game. The errors are normal. There's nothing missing - I simply removed the .mtl files from the obj models so that the same texture wouldn't load multiple times...that's the only problem though - error messages about missing material files, but that's okay because I reference the materials myself in the code so it doesn't load more than once.
Not sure what to do about the performance but I imagine doing things under WINE is not going to be as fast as if it were on Windows. i'm running a 2014 Windows 7 machine and it runs fine.
However thanks for trying the game. Yes, I do need to build in a tutorial system.