Comment by HypnoticOcelot

What do you mean by "really old"? My experience with games available on Steam has been fine(barring those big-budget ones), but I've had problems in the past setting up games from CD-ROMs that have DRM on them. Proton and Wine still don't play so well with SafeDisc or SecuROM, and traditional Windows workarounds(when applicable) often don't work on Linux.