Nintendo hardware is often targeted for homebrew, hacks and exploits, and we've seen a fair amount of them with 3DS and Wii U - attempts are also being made with the Switch. It's a relatively niche area of course, especially as Nintendo often forces modders offline by closing exploits through firmware updates.
Now that the Wii U has been discontinued it's likely to be open season on mods, and one we saw on Reddit is rather interesting in that it sort of makes the GamePad similar to a Switch. Not in all ways, of course, but as you can see in the video by Yahya14 they've produced a homebrew app that allows users to switch the TV view directly to the GamePad. Most Wii U games already allow mirroring, of course, but this opens the door for games that don't give that option, such as Splatoon.
It seems likely that this would be limited to offline play due to those firmware updates of Nintendo's, but it's another interesting example of how some like to experiment with and adjust Nintendo's hardware. Naturally it's still a grey area ethically and using anything like this breaks the user agreement of the system, though this particular mod doesn't seem to hurt anyone.
Is this something you wish Nintendo had made possible with games like Splatoon, especially as we've now seen the game's formula shifted to a single-screen format in Splatoon 2? Let us know in the comments.