I can't speak for the others but we checked this out at my party and I thought it was actually pretty fun. It has some single player and co-op stuff but we didn't try any of that, just went straight to the death match. If you have played Towerfall, Samurai Gunn or Duck Game it is basically the same idea... up to 4 players battle each other on a variety of 2D maps with a variety of weapons in fast-paced, one hit kill action. The twist that this game has is that every time you win a match, a ghost appears in subsequent matches that moves and attacks in exactly the same way you did...and your ghost can harm your enemies. By match 10 or so there are ghosts all over the place and it gets pretty chaotic... in a good way.
Though it doesn't *quite* live up to the games it is clearly inspired by, it's pretty solid on its own terms and probably one of the most fun multiplayer games I've played on the Wii U outside of the obvious Nintendo big guns. Worth checking out if you want some (local-only) multiplayer fun.
Yeah, I thought that it was really fun, as well. I'm definitely going to pick it up.
Actually, I liked the nindies demo quite a bit, even in single player. Having to deal with your own murderous ghosts was a neat twist.
It's kind of weird that Towerfall/Samurai Gunn/Duck Game/Nidhogg/etc. haven't been ported to the Wii U. They'd be so perfect for the console, with it's local multi emphasis and array of compatible controllers. Who has four Dual Shock 4s?