What does "work" mean? I mean, I'm fairly certain that the great majority of decent multiplayer games are fun to play for a match or two, whether there's levelling or not. I assume you're meaning "lasting appeal"? If so, then hell yes. I'm still playing Half Life 2: Deathmatch, and that has no leveling at all. TF2 has been brought up quite a lot, and frankly I don't see why leveling is NEEDED. All that gaining a level does in most multiplayer games is gain you either bragging rights or occasionally some sidegrade ability. It has no effect on the flow of the game, or the feel. Matches are still the same. Maybe it's just me, but I don't play multiplayer games for a sense of progression (Unless it's me myself becoming better, and that only really counts for stuff you play over looong periods of time, like TF2, into which I have well over 400 hours invested). I play them for a fast burst of adrenaline, and then back to real life stuff. If I want progression, I'll go play a Baldur's Gate, a Dragon Age, or an Elder Scrolls, not a round of multiplayer (The obvious exception being MMORPGs, but let's not get into those).