The game is fairly easy to understand and the base mechanics is fun to interact with. The charge the depletes and the polarity has a lot of potential.
I was having fun, and was imagining it would be interesting when the two colors of projectiles were mixed. But when it happens it has A HUGE spike in difficulty. I instantly died with no clue and felt like was not my fault. I think the game should start mixing the two earlier and delay that hard wave to much later.
In these kind of survival endless games, the pacing is very tricky to get right. This game (like mine) would benefit a lot from some quick playtests to tweak difficulty. I was not able to do this this time, the my game also turned out to be quite hard.
Other than that, the game is solid and interesting. Great job!