Game has incredible potential, sadly some turrets refuse to fire occasionally, dooming your run. 

RNG in this game is brutal, not receiving upgrades or facing wrong enemy composition easily ruins your run.

Economy is completely busted. Weapon upgrades don't appear to do much, and paying for reviving lost ships - you've guessed it dooms your run too. Ship upgrades also cost an leg and arm.

 
A lot of mechanics are poorly described, like some sort of cores you're supposedely earning after each run, but no infohow much you have nor how to spend them.

Worst still is that enemy stats keep growing with you until basic enemy units can pretty much almost obliterate your fleet before facing the big enemy guys. 

Graphics and potential are great, unfortunately confusing mechanics and unbalanced gameplay cannot warrant anything higher than 3 stars.