thanks for playing + for the feedback! the idea behind your first point is to swap as you approach the enemies, as then your invulnerable ship can crash into them and cause an instant kill.
Ohhhhhhhh I didn't know _that_, I found it very strange indeed that you said I could deal a ton of damage, but it just hurt me. Still would go with the keys + mouse approach tho, but that's just a tip, it's your choice :)