Side scrolling shooter - Day 1

Day 1 of having a play with ideas for the side scrolling shooter challenge. I really have no idea what to do about the no weapons thing .. I was fully intending to make a space shooter but now I'm not quite sure what to do...

Anyway I made a quick mockup last night with no physics (which is perhaps more arcadey) but then had a change of heart today and decided that as physics is free in godot there are a lot of benefits (realistic collisions etc) so I'd try and change the parameters to make it more arcade like. Or maybe I'll have a kinematic body for the player, not sure yet.

I've been originally thinking of a side scrolling horizontal space shooter like defender or ground attack, however not sure what to do with the no weapons.