It appears that the surprise Mark Rein was talking about is Aliens: Colonial Marines.
Later he tweeted:
So:
- Aliens: Colonial Marines is made by Gearbox (Borderlands, etc.)
- Unreal Engine 3 is on Wiiu
Later he tweeted:
MarkRein said:Congrats to Gearbox on showing Aliens: Colonial Marines on WiiU at the Nintendo E3 press event! #MadeWithUE3
So:
- Aliens: Colonial Marines is made by Gearbox (Borderlands, etc.)
- Unreal Engine 3 is on Wiiu