Very cool game! I'm surprised you were able to make so many different games during the time most people barely finished 1 single game!
I'm curious about your Leaderboard, what's the backend for it? I also seems like a really nice tool to be able to actually see how many people played your game, which is super practical.
My only complaint would be the rule of some games that aren't completely clear when you start them. I found myself looking at ticks going up in the music scale game when I thought I was actually playing well and ended up loosing. That wasn't really clear to me. And for some other rules, I only knew because I read some of the other comments before starting playing.
But except for that, super nice! Like the music, the sfx (except the special card selection one, it sounds too negative somehow) and the cute art.
Keep making nice game! :D