I like the pixel art and audio here .reminds me of Risk of Rain. The fresh air balloon is a really nice touch. One thing that comes to mind is adding some hangtime or coyote time; it would really improve the platforming gameplay.
You re absolutly right, the game needs some gameplay improvments. Maybe I Update the game after the jam - the Code is a bigbigbig bowl of Spaghetti xD. E.g. I can't add more then one zombie in a Level otherwise they cant kill the Player ^^'