"Also what kind of performance difference would there be with between Blitz 2d and 2d in 3d mode using a poor 3d card?"
It would have to be a very old/poor 3d card indeed not to have a performance edge over Blitz2D. Certainly any reasonably decent desktop machine that's less than 4 years old, and any decent laptop less than 2 years old has hardware 3D acceleration sufficient to justify this approach.
And someone with a 5y old PC with a lousy graphics card -- what's the odds they (a) download shareware games and (b) pay for them?
It would have to be a very old/poor 3d card indeed not to have a performance edge over Blitz2D. Certainly any reasonably decent desktop machine that's less than 4 years old, and any decent laptop less than 2 years old has hardware 3D acceleration sufficient to justify this approach.
And someone with a 5y old PC with a lousy graphics card -- what's the odds they (a) download shareware games and (b) pay for them?