I should probably play Undertale at some point...
Aw, man! Zack & Wiki! That is such an awesome game. For such an early Wii title, Capcom really got the motion controls right. It's one of the last times I felt like I was playing a "classic" Capcom game. Lots of secrets and references to other Capcom games as well. But boy is it hard! Probably one of the hardest games I've ever beaten. That next to last level is so hard! Mainly because it's really long and you have to do it all in one go!
By the way, I saw this video and though of you:


