Thank you for your feedback :)
We wanted to make more upgrades, but we stuck with the first ones we did due to the limited amount of time for the game jam, we also wanted to give 3 random upgrade options each time instead of showing all of them, a life upgrade was definably in our list.
We also wanted to make an upgrade that made you able to shoot while knocked back, wich would improve air mobility, maybe we will still improve on our game :P