the look of the game is poor after i find you can shoot forever i just moved from side to side killing the ships it needs work something to make the player stop firing so the gun can cool some new ships after you die an level up things could show up so you can make your ship better (faster,more HP etc)

past that a fun game to burn 5mins on but no real gamplay

Needs a display of controls (spacebar and left/right arrow keys) before actual play. Although sometimes they don't work? Way to restart after Health is 0. Either faster horizontal movement, or more vertical space. Animations of target and your ship exploding, given how large they are. You got lots of work ahead...

You can't respawn .-.

Gamingsprite disapears after being hit 3 times, without a game over screen. So just goes on without any player input possible. Also some explosion animations and better and louder explosionsounds wouldn't bad. Maybe some power-ups, different kind of enemies, and maybe smaller sprite OR a longer screen would be good, since the player is now in a bit of a cramped space. Making one these two changes would change the flow of the game for the better i feel. Also sometimes the enemy will hit you, but do no damage, and another time you will receive to points of damage for one hit. Also would be nice(but not essential) would be some backgroundmusic. All and all a decent prototype. Keep refining guys, you can make this thing shine

It is a game you can play.