It is possible to kill enemies after dying.
'- Before dying, beat Spiker
- Use the star to buy Drain
- Die
- Use Drain
While typing this, I killed Slimest (boss 3) after dying to (boss 2)
And then (boss 2) was also killed
Also why are there two Smileys (boss 4) now
Also I killed both
Wait that means I beat every boss while DEAD