I think this is okay if it's a first game but there's a lot to improve on. The movement is slow, the jump is not only floaty but non-variable. There are no instructions, so it was unclear if you could touch enemies. The foregrounds blend into backgrounds, which is terrible for platforming. There should be a victory animation at the end of the level, with movement halted. Heck, even the end should be more clear than an arrowed sign. The story cutscene is drawn out so I had to skip it. The player character is long but the level design seems to be made for a thinner character. The game says (DEBUG) on it. There's a mouse cursor in-game for some reason. There's no way to quit the game with menu options (I had to exit fullscreen then close the application). At the most critical, it's just kinda meh.
I don't say this to be cruel. I think this is a functional game and a good start.