Very fun and visually pleasing game! The gameplay was just shy of being repetitive, which in my opinion is the best half-way point between frustration and boredom. The endless barrage of sweet sweet eye candy isn't a minus either, and the game was just challenging enough to be addicting.
A couple things, however, took away from the game a bit.
For one thing, throughout my entire first playthrough, I was clicking between the perk and "talent tree" menus, wondering, "where the hell is this challenges page and why do I keep getting random ones??". It was only after I beat the game that I saw the page on the MAIN menu. So, if you could please, add the challenges menu into the in-between-battles screen.
Also, the "talent tree" is... not unbalanced, per say, but perhaps... unduly strict. It was after I chose the Double Shot for the first branch that realized there was absolutely no going back, even for talents just one back, which made my life incredibly miserable because without shields I always get pummeled into space dust no more than 2 or 3 minutes into each fight, so I had to start over. That said, maybe you could institute a more lenient system of choosing talents? Maybe a system of buying them instead of strictly PICK THIS OR THE OTHER, NO TAKEBACKS. Or at least add a warning saying that <-----
Overall, a really well-done shoot-em-up space top-shooter, nothing INCREDIBLY innovating but fun nevertheless. Good work.