Oddly it's possible to simply walk off the top or bottom of the screen. As far as I can tell you could just walk off infinitely as long as the chumbuds don't catch you. You've also got something odd going on where the tridents seem to spawn in the wrong area altogether sometimes. I assume it's some weird global to local or local to global space translation issue (I had a similar problem with Gun Fauna.)
I do appreciate your boxy programmer art, games made of boxes paved the way to games made of other shapes. The homing tridents are fun to play around with too. With a few tweaks this could be a score based endless shooter like asteroids!
and people LOVE asteroids!