Give yourself the credit
A very competently-put together little game. A few pointers however...
For example your tutorial is... I don't want to say unnecessary, but for lack of a better word, it is. You have good level design. For example. "Go through the door to advance." Oh frabjous day! I never knew what these door things in real life were for! They're like magical portals to other realms!
Also, give your level design some credit. "You can hold to jump higher" Again, you placed a platform out of tap range. I figured it out within 2 seconds that I needed to hold the button. I don't need a giant flashy text box to tell me I can't jump that high, I just realized it myself. Your level design teaches players through play. Same with the locky door mechanic. Cut the signage altogether. "Oh hey look a door this level's easy oh wait there's a giant keyhole thingy on it. Why can't I advance? Wait, I'll use my brain! Hm... well what usually goes in keyholes..."
See what I mean? Also, if you're gonna have the cute little advance stage thing in a mainly keyboard game, please, please please please make it able to be selected through the keyboard. It's very awkward to have to reach over for the mouse every four seconds to click "Yes I would like to continue playing, you just asked me at the end of the last one."
Overall, a wonderful aesthetic and well executed, but the tutorial feels a bit like I'm being hit over the head with signage.