The Wii version of Monster Hunter Tri.
Japanese 3DS owners will soon get into the Monster Hunter racket with a port of Monster Hunter Tri releasing at the end of the year. Monster Hunter Tri G makes use of an optional Expansion Slide Pad accessory to give 3DS users a control setup similar to that of a Classic Controller Pro.
Tri G retains the water elements found in the original Tri, which will have hunters occasionally take a dip in oceans and lakes to find their prey. Local multiplayer is included so you can meet up with your buddies to do some co-op hunting.
As for the Expansion Slide Pad, it is a cradle-like accessory that attaches to the underside of your 3DS. You can find an image of the accessory in the gallery below though it may not be readily apparent that the Expansion Slide Pad also includes three shoulder buttons to use in conjunction with the 3DS's L button. The shoulder buttons are arranged like the Classic Controller Pro's ZL and ZR triggers.
Admittedly, this accessory is going to take some getting used to. Aside from the unusual control layout, you'll have to hold the 3DS a little towards your right side to keep the screen centered.