If you’re looking for a challenging game to play on the Wii U, Aliens: Colonial Marines might be a worthwhile choice. Brian Burleson of Gearbox has said the game is “exceptionally hard”, explaining that:
To make [the Xenos] feel as threatening as they are in the franchise, they’ll kill you in two or three hits usually. That’s pretty vicious. You add different things like where they’re coming from, you have more of them, you have them coming at you more relentlessly and their AI is more.
There’s also a mechanic that will scale the amount of enemies coming at you depending on how many people you’re playing with during the co-operative mode.