Currently, the gun of catalysts has massive weaknesses of slowness, necessity to prepare, and unreliability. But what if the charge shots tagged, even if the enemy is guarding or invulnerable? This may seem abuseable at first, but if you have to hit them in the first place to make it blow up. If you can't hurt the enemy with normal shots, you can't trigger the charges either. The idea is a way to rack "Damage" on invulnerable enemies, and then blowing them up when you see an opening.
Tell me what you think. It just occurred to me today when I was trying to think of ways to get it off that "Collect the dust shelf".
+1
The gun is almost useless in those situations otherwise.