Whoah, those are some really tough Emojis!
If I started shooting an Emoji as soon as it appeared on screen, I could just barely kill it before it left the screen. The power ups helped, but I'd step their health down by about 50% or more.
It does change the formula from your traditional Shmup a bit though. It's less about clearing the screen by hitting every enemy and more about picking a path through and clearing just the few enemies you need to get by.
Otherwise, lots of fun! Super cute art, and the enemy dispatch patterns had a nice variety to them.
one last quibble, I didn't hear any sound effect for when I shot, wasn't sure if that was deliberate or a bug or maybe I was just not hearing it over everything else that was going on, but it seems like the player gun should make a sound.