Thank you!
Yes I added in the ability to restart the level to spawn new enemies. from the pause menu (Tab/Start) you can select New Level and you keep your ship and can keep going. New Character starts you with a new ship and new pilot, but you keep your credits. I added that on the last day of the jam. I crammed a LOT in the last day of the jam. I talk about it in my Katamari Mech Spacey Devlogs, expecialy my Day 9 devlog.
Making them stronger was going to come, along with randomly generated ships instead of randomly skinned ships. Alas, time. And the ship editing system that would allow you to spend your credits wasn't quite done.