One thing that I got advice on both this game and a lot of my platformers is "The platforming controls could use some work" or I don't feel like I'm in control and well the same I could say here I understand that you didn't want the characters to just go from 0 to 1 you wanted them to have a transition but decreasing your horizontal movement by a fraction when you aren't pressing a or d isn't hard and it can add a lot of control without sacrificing the "smoothness" of it.
If I was to give one advice is focus less on the amount of content like having tenths of levels and polishing the basic gameplay you'll end up with less but of higher quality gameplay and on when making a game it's all about quality over quantity and this is especially true for game jams where we understand that some people don't have time to seat making levels for hours but we still like those games if they have good gameplay even for the 3 minutes we play them