Great job, especially for your first game!
I'd echo the same as the other comments: the speed is a bit fast for the dexterity you need to land on those platforms and it made the game extra difficult. I'm not very good at 2D platformers in general, but this one was definitely up there in difficulty! I think when you make a game, you get used to the controls from hours and hours of playing it, so it can be difficult to balance.
I really enjoyed the story! I haven't seen a game jam game yet with a back story, so that was fun to see. I think the text ran a little fast for me, but I caught up to the pace and was able to get it.
I think you have a nice consistent art style and a good solid game base here.
Nice job! Especially for it being your first game, I think you made an impressive first game :)