I'd say you've got some good core gameplay here with trying to deal with the large number of enemies and weaving through them to get the power-ups. But I do think it would help to have more feedback about when things take damage though, like have some hit particles/hit sound when hitting the ghosts and some sound/on screen effect when the player takes damage as well. Aside from that, I also thought the gun was a bit static, it would be nice if there was some animation for reloading, or a kickback when you fire it. Either way, what you've got here is still good, nicely done.