Borderlands: Continous fun!
1. It's just great. The battle system, the skill system, the action skill, the levels.
2. How much levels affect you: Attemping bonehead at level 10 is way different than attempting him at level 11.
3. Weapons - 17.5 million weapons known to mankind, how they are balanced, the chance to get an epic item and how after 3-4 levels you need to swap it. Oh, and the snipers/revolvers are epic.
4. The Quests: It's not like Call of Duty that there is 1 continous quest that you have to finish. There are so many side-quests, that can help you level and get you new weapons.
5. The EXP system: You can't stay a few levels grinding in the same zone. If you're a level 6 trying to level from level 2 Pup Skags just don't expect for too many results.
6. LAN gameplay, and how monsters get stronger and give better loot while playing with more than 1 player.
7. Criticals - Sorry but I just had to put this in a different section from the weapons. I get up close-ish, zoom my Sniper/Revolver and BAAM! I don't think a monster my level can survive such epic headshots.
But there is only 1 thing that dissapointed me in this game, hence the 9.5 - The lags online. The whole point of an FPS game is real-time action, not delay action. I can't land headshots as easily as I can on Single/LAN.