Congrats on making your first jam entry! Don't get discouraged, as even simple platformer movement and jumping is not easy to get working properly - there are probably a hundred other people that tried to do what you did and didn't bother to submit because they didn't get it done, so well done on that milestone you've cleared. Even among those that do get jumping working, their jump mechanics often don't feel right because gamers expect a certain jump feeling that they've gotten used to over the years, but you seemed to get the jumping physics well and you don't have the common "jumping in mid-air" bug either.
Good job on the start of your development career!
Would you mind trying mine out and leaving a rating for me too? I'm trying to get past a dozen ratings.