to play first ab3d and gloom, 020@28 mhz like Blizzard 1220 are quite enough.
maybe, lates level with big enemies require 030@40/50 mhz.
To play breathless at maximun frame rate, best to have a 040@40 mhz, but with 030@50 mhz is good playable in 2x2 or 1x2.
to have a fast processor, but cheap, 030@50 is a good choice
