Perhaps you've already heard this, but the gun-and-jump PC classic, Bio Menace, is freeware! It actually has been freeware for a few years now, but back when it was first made so, a person would have to handle the nitty gritty of downloading a PKZIP archive, extracting it, knowing about or finding out about DOSBox, or alternatively having a DOS PC for gaming, combining all the pieces, and making things work. But now, thanks to the convenience that is the GOG.com release, all that is no more! If you follow this link:
http://www.gog.com/game/bio_menace
You will find a ready-to-go copy. Just go to GOG.com, "buy" the free game, download it, and run the setup program. The installer will set up DOSBox with Bio Menace and create shortcut icons for you. That's all there is to it other than double-clicking the icon and getting ready to play! Enjoy your Apogee / 3D Realms classic!