Aliens: Infestation has been properly outed by the ESRB. We first heard about it when it was revealed as a canceled project, before the OFLC revealed its name. Since then, SEGA has refused to officially announce the WayForward-developed DS shooter, but the ESRB seems quite sure it's happening.
"This is a sci-fi action platformer in which players control a marine squad on a mission to eradicate alien creatures," describes the ESRB. "As players run and jump through side-scrolling levels, they use rifles, pistols, flamethrowers, and explosives to kill enemy soldiers and aliens (i.e., "xenomorphs"). The frenetic battles are highlighted by realistic gunfire, explosions, and cries of pain; injured aliens emit green splashes of blood before collapsing to the ground.
"Some sequences also depict red blood spurts when human characters are killed (e.g., an alien bursting out of a man's chest; characters getting bitten by aliens). During the course of the game, players can enter a locker room and see a male character whose buttocks are briefly exposed. The words 'a*s,' 'bastard,' and 'hell' appear in the dialogue."
WayForward is a fine studio, Xenomorphs are badass, and sidescrolling shooters are great fun. Looks pretty much like the perfect storm of awesome to me.