Gunbound is a game I used to play awhile ago and sometimes go back to for a bit.
x] I find it pretty enjoyable - though (for me, I don't know about you) it's simply not a long term game for me.
It's a battling game, where anyone can make a game room and they're different settings for the rooms. Each game you can choose a diff. battle vehicle. There's 1v1, 2v2, 3v3, and 4v4.
You DO "level", but the only difference that levels makes is that you are able to enter different battle zones (beginner, pro, free-for-all, or something like that). You gain experience by winning lots of battles, and even when you lose but did some nice shots.
Cutsey-cartoony style. You also win gold when you win battles and you can buy outfits (with stats) for your character. Some items need in-game gold to be purchased. Some items need real life cash. Some items have a purchase option of either.
=-=...Talking to much, heh? Overall..fun, casual game. Some ppl find that after awhile it doesn't take much skill because you get really used to it (but I never was really pro so yeah...).
Anyway, good luck finding yourself a game =].