Thanks, Kelvin! I totally agree with all the suggestions, these are all either my to-do's I couldn't implement in time or things I wasn't aware of like the sizing issue. I only followed a tutorial from GDquest before the jam (link for occasional interested readers), toyed a bit with platforming on my own, and dived right into the jam to have a clear goal and work through all the steps in limited time. So as I was learning, things were getting clearer and easier. The level 2 idea came to me the night before deadline, and I pulled an all-nighter to realize it. Then I also noticed how much better it came out to be than level 1, but it was already an hour or so to the deadline. So basically it's a product of the learning process - a few days of struggling with basics, then one night of feeling almighty and giving my all. I was also learning to draw along the way. Here, have my prototype vikings and a wasp as a souvenir, haha 
P.S.: Loved your game! Spaceships, nightmarish organisms, and the touch that your loss is actually a win for humanity (or some other race) that fights the infection.