I doubt anyone but CMG has details on this, since it seems that he hasn't even announced which game it is yet. But if you check his Twitter, he says that it's a dual-sticker shooter and later says that someone already guessed the game. Looking at all of the tweets chronologically between those two, I am led to believe that it is either Mutant Storm, Mutant Storm Reloaded, or Dead Horde. I think a Mutant Storm game would be most likely because he also said it was a game that was already announced for iOS.
Game Center ID: SlighMD; Battle.net: SlighMD#6986; Vainglory: SlighMD Currently playing: Hearthstone, XCOM: Enemy Within, Vainglory, Dodonpachi: Ichimen Banchou Waiting for: MHFU for iOS to be fixed and Titan Quest