Dishonored,
https://www.youtube.com/watch?v=INPKd4JGtsk
near perfect game play, ignore the story/skip it so you can jump back in to the killing, even has some expansions with modes focused to that gameplay no story nonsense
sorta like Call of Duty meets Guildwars, with slight megaman platform possibilities in first person
Magicka,
https://www.youtube.com/watch?v=g_XP9OBWGKo
no story as such, (they got some weird made up blabber goin on but thats not what its about), just kill anything that moves with fun selfmade magiks, while you go around
Portal 1+2
https://www.youtube.com/watch?v=9vMV2hEIFG0
first person puzzle platformer, sorta hilarious comments/stuff going on in teh background while you jump and puzzle your way through the levels with a teleportation gun
Orcs must die1/2,https://www.youtube.com/watch?v=CqRcgaZnxh4
https://www.youtube.com/watch?v=OXkK4LCO2dg
wave based "trap" defence game
Shadow of Mordor,https://www.youtube.com/watch?v=VBPmkfu_zs8
3rd person action game, sortal like same lvl of story as in assassins creed or GTA game, mainly about teh action
Oh, and Bulletstorm,
https://www.youtube.com/watch?v=vOFNdbIVFT4
FPS with some extra fun twists on the regular FPS combat, slightly less than Call of Duty lvl of story,
and Warhammer 40.000 Space Marine,https://www.youtube.com/watch?v=nb50aAFiOpM
straight up Warhammer slaughter in 3rd person