I was extremely disappointed with this title.  You will like it if you like Goldeneye, but definitely go with Goldeneye over this game.  The multiplayer is 50 times better than Goldeneye, but the cheats and single player levels leave EVERYTHING to be desired.  For one thing, it requires more sneaking around because one missed shot hits the wall letting the guards know of your presence who will then hit you with perfect accuracy and kill you in a matter of seconds because of your quickly draining life meter.  You also run out of bullets faster and reload much slower.  The difficulty is just about near impossible.  If you can't beat Goldeneye with EVERYTHING as in cheats, bonus levels, record times, etc, DO NOT BUY THIS GAME.  You can't beat this game on Perfect Agent unless you're a game tester, and I'm sure even they had problems.  The game is so hard it just totally degrades from the fun factor.  The plot is also absurd.  Aliens and such.  Ha Ha.  Amusing.  DON'T WASTE YOUR MONEY!  I strongly reccomend going for Goldeneye rather than Perfect Dark.