The initial few stage is a bit of a slow burn until the upgrades start to kick in. When it does though that's where a lot of variation start to come in, it just might take a while to realize. Also might want to make it clear that you could un-upgrade
The main aspect that makes it a bit hard to get used to is probably the controls, There's a lot of different buttons when many of the buttons could have shared functionality. The friction is a bit slippery too at least for no-upgrade platformer. I eventually got around to A+ on every stage though, so it's not detrimental tier it's just mostly the early game that might turn off new player.