The best games I've played are Killzone and Shadow of Mordor.
Killzone is a excellent first person shooter. Campaign is decent, not as good as Killzone 2, but enough variety in the ways you can play to make it really enjoyable. Online was excellent, it's not like Cal of Duty and Battlefield, which is full of snotty annoying American 9 year olds. But the game has been out since launch so the number of players online might be quite few now.
http://uk.ign.com/articles/2013/11/1...ow-fall-review
Shadow of Mordor is an excellent open world sabot game. Set just before the Lord of the Rings, you play as a ranger who goes around slaughtering orks, often in slow motion which makes it thuroughly enjoyable.
http://uk.ign.com/articles/2014/09/2...-mordor-review
I've not played the sniper game, so I can't comment. Sorry.