Understood but perhaps I said c) in a backwards way. I mean I made the superficial observation that most of the guts of the game are inside these vpp files.
So suppose I were to install the full game. Then I find the file(s) that the exe will hunt for to actually play level content, delete them, put the demo vpp in there instead, possibly rename, maybe make some dummy files for the others I deleted, and run the game as normal. This way, the file structure is basically intact, save for the file sizes and file contents of the levels themselves (which may or may not rouse the game's suspicion). Most importantly, the game size would be way lower and closer to demo size.
Also these wrappers... do they basically take 3dfx function calls and translate them into DX calls or is it API specific (3dcif or whatever) or is it just like software emulation? Basically I'm asking if using a wrapper would qualify as "hardware accelerated" in the sense that it actually uses the 3d card to the same extent it would be used if it had native support? Would I google something like, "Ati rage ii glide wrapper for descent freespace" or is it just "ATI rage glide wrapper"?