When Wii U was unveiled, just a few months after the arrival of 3DS, some wondered whether the GamePad's screen would feature autostereoscopic capabilities like the handheld's screen. It didn't take long for that idea to fade away, as the realities of a glasses-free 3D screen that size, as well as its constant use as a touchscreen, made the idea a no-go.
With that in mind, however, there's no reason why Wii U games can't be playable in conventional 3D with the use of glasses and/or 3D TVs — Satoru Iwata confirmed as much way back in July 2011. Unlike 3DS, however, the emphasis is on developers to make the 3D happen, rather than it being a feature built into the system. For Wii U's part it just needs to have enough power to process the graphics, and considering that PlayStation 3 has a number of 3D titles, it's easy to see why Wii U is similarly capable.
This anaglyph 3D — which requires the use of specific glasses — works on any screen, and a report has dug up confirmation that Assassin's Creed III includes the option in the Wii U version. As it's a game that allows you to play solely on the WIi U GamePad screen, meanwhile, it stands to reason that, in theory, you'd be able to play this game in 3D either on your HDTV or the controller's display. In this case you need Inficolor 3D Glass to enjoy the effect, with this brand having a direct tie-in with the game; it's all down to developers, remember.
So there you go, you can technically play in 3D on your GamePad screen, but it depends on the game and owning the right pair of glasses. Is this something you'd be interested in trying on the controller's screen or, more likely, on your TV?