The WiiWare has been pretty sparse with co-op releases, but it's beginning to show some promise. With titles like Eduardo the Samurai Toaster and now Onslaught - the WiiWare looks like it could have some great original cooperative titles.
Onslaught is coming from publisher Hudson Entertainment, and will feature Wii-Mote controls. Shake the controller to reload, toss a grenade with the Nunchuk and drive a mech with your butt....ok I made that last part up.
Four player online co-op is a rare treat for Wii owners, and a gamble for Hudson - hopefully it works out for both parties! There's no word on a solid release date or a price yet for this title, so be sure to check back for details.