I'm a huge fan of shmups and thank you for bringing another one into the world. So I'll just rattle off a couple things I noticed, and take the placeholder assets for what they were.
+Really like the speed-change ability, helps to adapt to both more precision projectile avoidance and quickly getting out of harm's way for huge boss attacks.
+Music and sound effects are solid. I don't know if those were ripped from anywhere, but hey they work.
+Weapon upgrades work like a dream, shootan is just sweet in general.
-Hitting the big cube enemy with the Homing weapon didn't give any indication of collision unlike the default blast.
-Fisting boss looks a little jank when he swaps immediately to the open mouth sprite without any indication of charging the laser.
-I think the mountain backdrop could use some animated elements like low opacity clouds or something that continue moving when the screen locks for a boss battle; just to keep the whole thing from feeling so static.
-If you Game Over right before the "Warning" text, it still plays so that both the warning and the game over text overlap each other.
Overall, keep up the good work.