Oh I'm an idiot, I had no idea those single disc versions were combined and you have to load both images on each drive in xm7. Forget everything I said about the 1 disk stuff then!
Unfortunately even after trying 2 different combined disc versions of Deep Forest it still seems to be the bad dump (I've never come across a bad dump of Death Force though, all of those work fine)
I'm hoping maybe I'm just being an idiot again and these Deep Forest dumps are correct, but I mean anyone else can try it and see for themselves. Start a new game, and then you can press 1 and 2 to skip back and forth between the 6 stages in the game. You can skip to stage 2 where you start on top of a treasure chest, and pick it up to see that nothing happens (the item chests in stage 1 give you more power and stuff)
Anyone who plays through the game normally without using the level skip buttons will realise how broken the game becomes when you attempt to progress any further than stage 2.
Also the pyramid level bug can be seen in this video:
http://www.youtube.com/watch?v=nSlIpseoUrU
Watch from about 5:00 onwards, the guy gets the main chest in the pyramid and then becomes stuck in the menu. In-game I've tried all options to get out of the menu but nothing works, and the sound becomes totally glitched.