And I still say that Lemmings (1) has the most enjoyable levels of the original games (except for a few duds like Hunt the Nessy...) as they are always fun to come back to, mess around with, try different routes or the various challenges we've come up with.
Lemmings: 6 [+1]
ONML: 4
Holiday: 2 [-2]
Tribes: 3
Chronicles: 3
L3D: 6
Paintball: 6
Revolution: 7
Playstation: 3