Heres some changes that could be made: more fragments upgrade for csp, heavy hitter is meant more for spamming normal shots than charge shots, so maybe some more normal shot upgrades and burning nightmare, you dont need 2 drilling speed upgrades because your character cant move quick enough to actually utilize it, so take something else tier 1, c4 works best with more damage tier 1, and then more ammo in tier 3. the one that makes it explode after it takes damage actually is a downgrade.