Hey, thanks!
The ammo crates should actually give the player twice the normal amount of ammo when they have the rotary cannon, but I definitely agree on the grub mission it doesn't feel as impressive as hoped. Honestly it works best as a close-range weapon to take out the mechs quickly, especially as they can't fire back when they're flashing white.
There'll definitely be weapon switching between primary and secondary, I planned that from the start but don't have enough weapons to do that yet. Thanks for the feedback!