That's totally fair. If you plan on making a post-jam version, I'd definitely recommend going beyond the scope of just "damage" as far as the textures go. For example, the fire texture could have DoT or the ice texture could make the boss attack slower, stuff like that. It'd definitely improve the game if the different bullet types actually did totally different things, though this is 100% just a minor nitpick rather than an actual major criticism of the game.