At first I thought it was impossible to survive for 3 minutes given how the missile is faster than the player, but then I realized it was possible to utilize the player's greater maneuverability. Moving around in this game feels more like a graceful dance with your missile as a partner than like a frantic chase, and the music reflects that.
The graphics are beautiful, too.
One thing I don't like is that enemies don't telegraph when they're going to shoot and in this game that's important because you often have to swim close to them in order to lure your missile into them. I'm not sure how it would be telegraphed best, though...
Also, I think the player's hitbox is too large. It might be more fun with a few more enemies but a smaller player hitbox.