In a word: Fun
Well, for starters, the graphics are great. They're not too cartoonish, but not too realistic, which means you can take the game seriously. The plot is a mix of classic James Bond and a bit of sci-fi, which I really enjoyed. The cutscenes where very smooth and great to watch, not like some games where you have to listen to droning voice acting and jerky animation. I liked the gameplay, too. Very smooth, very professional. This makes for some top-notch multiplayer games. Like many other games, you can keep playing the game over and over to unlock secrets like characters, levels, and powerups.
Though the controls weren't customizable, but the setup was standard to most games. Bots were alright, with a huge difference between easy and hard mode. Starting a multiplayer was a little tricky, because everyone can change the game options even when they've been set by another player.
The Bottom Line
Agent Under Fire is a fun game to play. I love single player because is challenging, but by no means impossible. Multiplayer is always a blast to play (my favorite MP games are when I have one other person and I go up against a team of very difficult bots). Though this game isn't in every gamers collection, once you play it, you'll want to keep playing it again and again.