Decided to go with what I thought was Yimib-Echo but is actually Yamab-Echo.

I'll likely not be able to work much more on this till a week from now, Comments on the initial design are very welcome.
The premise in a nutshell is that you play a game like the "dancing goron" game in Zelda oracle of ages (dancing subrosians or whatever in seasons), where the leader makes a pattern and everyone else has to repeat it, except in this you're bouncing the pattern back and making the notes bigger. You can add more notes in, but just mashing won't get you anywhere as the aim is to get really big waves bouncing around for a million points. I'd also like to make a jam mode where 4 players could each play a 2P game to have a little song going on, as each of the moves (I'm thinking of having ABXYLR+Dpad, but I might drop XY because of the whole NES basis) will have a sound.
There will also be a few different difficulties, Easy will only use A+B, Light will only use ABXY (OR ABR as the case may be), Standard will use all the buttons that are available and Heavy will use all the buttons + the Dpad. Challenge will likely be lowHP mode (sudden death).
VS would be interesting. You'd want lots of points, so you wouldn't just mash, but you'd have to be devious. clap diddy clap clappa, clappa clap-clap chicka clap da clap da clap clap -repeat-
In 1P mode, each "save" will have a YAMAB that you're training to echo stuff (it's a game they like). As they progress, they'll get better at mimicking you and also start to add their own stuff.

Harder modes will only be available once your YAMAB is at a high enough level. (there might also be a "free" mode where you can do whatever)
In all the games, the game is over when you miss enough claps to cause an avalanche, and you slide down into the valley together and hug or something to be adorable. (softens the GAME OVER text above a little

)
Should be interesting enough, I'm kind of glad to be doing something that isn't violence orientated.