Get Lethal Enforcers 1 & 2 for PS One. Both games are on one disk.
The Genesis versions are good but the PS One versions are arcade perfect ports.
Just played through them yesterday.
Also, if you are a Lethal Enforcers fan you have to check out:
Freedom Force (NES)
Sunsoft made it back when they could do no wrong. Play through a few stages and you'll see that it has to be where the inspiration for Lethal Enforcers came from.
House of the Dead 3 for the original Xbox is great and when you beat it an arcade perfect port of House of the Dead 2 is unlocked.