Good guess, but apparently the encryption sticks regardless of whether I tone down the English on my speech.
If motivation is need I can provide a batch of fresh warm cookies to the person who decodes these files. They'll most likely be in jpeg format if you're not allergic.
;) Have the game image here, will take a look later. But as far I can see... I've never seen anything like that, and I've been around for quite some time now. :-\ Could this be a case for HCS?
It is "encrypted", and it seems like a very simple scheme, a lot of structure (RIFF header and probably seek tables) shows through the XORing. Not understood yet to the point where I can meaningfully decrypt it.
So far, the key stream starts with
F2 60 59 BF A6 67 BB B0 82 DD 24 BA 6C 14 62 31
It appears that each of these is a 32-bit little endian integer, this appears to repeat for the next 16 bytes with a constant (?) added to each. For the first column (0-3) it looks like around -0xA692000 and for the last column I'm seeing 0x14D5000 or so. You will note that there is a nice -8x relationship between these, so there is probably some simpler bit twiddling going on that I haven't penetrated yet.