Excellent game, let down in a few areas...
The stealth attacks and minimal, sneak up from behind or hang from a vantage point, which ultimately results in someone noticing you. The gadgets are useless against these enemies if there is more than 2 of them and there just doesn't seem to be enough quick take down methods which leaves you surrounded all to often.
To be honest i've very much enjoyed this game until i got to the point where you have to shut down the penguins communications jammers and then i've simply run into no end of trouble with blokes with guns.