Nice game, the chiptune matched the presentation really well.I liked how you'd fleshed out the alternate dimension stuff more than I did - I wanted to include higher risk / reward there but settled just for invincibility.
Only suggestions I'd have would be to have the main attack autofire when the mouse is held down. And maybe in a sound notification when your dash is ready would be nice too.
I won in 1:25 on normal and lasted 2:41 on endless. I was trying to be clever and use the pierce feature on the player's weapon but ended up being blasted to bits :) Good game.