That was an interesting game. Really liked the ability to double jump, it made dodging the enemies a bit easier! I have to confess, I actually exploited a bug in Level 3 by jumping over the zombie's heads (with the double jump!) and then getting them stuck in the terrain so I could actually kill them and get to Level 4, which I was super excited about :pp I couldn't make it past Level 4, unfortunately.
For future games, I really recommend doing some playtests with your friends/family to get their feedback on the game! We personally managed to do one playtest for our game, and it helped us a lot. We made a few changes to our game according to the feedback, and those changes were for the better. Sometimes you think the players will interact with the game in a certain way, but they end up doing something completely different. Which is why playtests are so valuable! They provide a different perspective for the game.
Good job on finishing the game for the jam! Out of curiosity, how many levels are in the game?
Good luck in your future projects! :)