I'd recommend sniper elite 5 to anyone wanting a good co-op game. Me and swooshboy are currently going through it and it's class, from thinking we are the top kiddies in the SAS and being awesome at stealth kills, to walking round a corner into the path of a guard and alerting the whole island
it's great fun, missions are proper lengthy too if you do it properly. It's not overly complicated either like a lot of games end up, just fun from start to finish. Some great laughs sneaking up on the enemy then they turn round and the sheer panic in our voices "shit shit shit" and the obvious "feck" once we are seen.
Got quite a bit of replay value too, we thought we'd been thorough so far but feck me we've missed allsorts.
Also, testicle shots will never get old.