Fun little idea! I think there's a number of improvements that could be made, just going to list a few and hope they're helpful. The game overall had a great idea behind it, very fun conceptually - I love games with mini games like that, especially when the mini games make sense within the context, which as far as I can tell they all did very well.
But I didn't fully understand what I was supposed to do with most of the mini games. While eventually stuff kind of made sense if I just clicked about randomly, when there are some different mechanisms involved, it's always best to have some kind of explanation, even if it's just on the itch page itself, for how to achieve your goals, or otherwise the point of the game can be lost.
You can turn on YSort for your scenes very easily; anything that inherits from Node2D has a YSort property on it now, and if you have that, your character only shows up behind things when it is actually behind them, while appearing in front of them when it is supposed to be in front. It takes some tweaking, but hopefully that's a helpful tip for you!
A simpler tip that is perhaps my own pet peeve is to include WASD as up-left-down-right controls in your project settings under the input. It's not hard to do, and can make it easier for some people who don't have arrows on their keyboard to play the game.
Finally, even though there weren't a lot of animations or anything, it's still useful to have your character flip when swapping left/right. The easiest and generally best way to handle that is to look at the sign of your input.x and do something like this:
var sign_x = sign(input.x) if sign_x != 0 and sign_x != sprite.scale.x: sprite.scale.x = sign_x
This will make it so that it flips left and right, along with any children, such as hit boxes, of your sprite. Note you don't want to flip the physics body around this way as it can cause weirdness in Godot.
Overall, it was an impressive effort for a short period! Several mini games can be really hard to pull off.