At this very moment? Doom on XBLA.
Been playing H5 but that turned out to be a disappointment with a very short dissatisfying story, no splitscreen, no forge, and microtransactions in the form of "requisition packs"...and don't get me started on the story...15 missions, 12 of which were played with Spartan Locke (and of those 12, 3 were just walking around talking to characters and basically wasting time). the remaining 3 are with Master Chief, who I wish had at least 50% appearance in the game...and the ad campaign was completely false advertising how the game was going to pan out. Locke and Chief never have a face off and badly injure one another like in the huntforthrtruth trailer they did...also the final boss battle was repeated 6 or 7 times...lazy game design at its finest...at this point I've lost hope for Halo...I don't even want to see what multiplayer is like...
Guess I'm still waiting for that awesome Xbox One exclusive that will be worth buying and well worth what I pay for...and it's definitely not BattleFront (EA) because that already looked like a half assed 1/3 of the game released and the rest to be fixed by paid-for DLC...just like Destiny that was another huge disappointment...
I'm done now...for real...