For once you get to play as the alien and it's decent enough but has some flaws
Gameplay- At some points you are in your flying saucer using it's variety of weapons to destroy buildings but most of the time you are on foot completing missions or just messing about. The missions are varied but a lot of the time all you really have to do is shoot something which lowers the variety a bit and gives it a feeling of sameness. You have a host of different weapons at your disposal and it's always fun to blast some poor humans just for the sake of it.
Graphics- It doesn't really push the ps2's graphical power and could have been crisper but the graphics aren't exactly poor.
Sound- If you read the minds of the humans when you are disguised they often say funny little remarks which are always good for a laugh. The guns sound unique and Crypto the alien you play as has a rather cool voice.
Value- The game is decent value for money because there is replayability just not all in one go once you have cleared the story. It's fun to just drop into every now and then for a 15 minute blast.
Overall- The game is fun but repetitive and could have done with more variety. The fact that you play as an alien offers something different and you could do a lot worse than pick this game up especially now that it is down in price.