The game title should be "The Square", since the big giant squares are made out of many pixels and even the bullets aren't a pixel. They all even have anti aliasing, so its even less pixly.
Enemies are triangles. If they would be squares they would be less distinguishable of course, but you can make them different colors and sizes.
How do you plan to introduce different enemies, when you have the pixel limit going on? Just bigger squares/triangles/circles with different attack patterns?
Also, its kinda hard to see the small bullets fly at you, since triangles spit out bunch of particles that look the same. But then again, it seems the player can soak up lots of them before dieing.
Balancing is something I've been working on more recently, as well as making the bullets a bit more visible to the eye. The anti-aliasing is planned to be removed, I agree that the pixely look is a bit ruined. But I'm still on the fence about keeping it or not.
The plan for the game is to make it pretty much endless, with the goal to getting as far as you can. And yes there will be different attack patterns, completely random patterns of spawning, and the occasional random boss fights later in the game.
Thanks for the feedback!