i like the concept and the synergy you had to focus on
some idea
- Make a healing / shield module ( maybe it come further , but I don't see one )
- Make it a rogue like buy using the score as many in a prestige tree where you can buy speed upgrade , damage upgrade maybe
- Add some drones
- collecting one or firing one
- Maybe add a drone launcher module for it
- For bosses , add a progression line on the screen top