A cute simple platformer with some nice color choices. I think the ideas introduced are done in a sensible manner that makes sense but doesn't bring a ton new to the table, in the future from personal experience I recommend:
- playing with having sections that go in directions other than just right, I personally find that creating a downwards section for example just naturally introduces new and cool ideas
- experimenting with giving the player more function than just running and jumping, which is a bit extra but opens up a ton of potential for exploring avenues unique to your game. Technically this doesn't even have to be a movement gimmick either, it could be an environmental gimmick
- playing with structuring of the terrain when making things. even just adding walls and such can help control where the player can go, which can add a bunch of cool new avenues for movement. This can also be hazards, which are also explored a bit here
A lot of words but my main thoughts are that this is a great start and everything that's done here is done pretty nicely! Would love to see more in the future.