The core concept to Radiant LUX, this abstract-themed 2D shooter is simple: destroy enemies of a color, and you level up your shot of that color. You also deal more damage to enemies of the same color as your shot.
You start out in the Red refraction, which spawns red enemies. However, occasionaly an enemy of a different color will appear. Kill that intruder, and a portal will spawn that leads to his refraction, which spawns enemies of that other color. That way you can get a new attack from that color and level it up (oh yeah, leveling up each color provides different attacks and passive abilities to your vessel).
Also, after gathering a few levels in different colors, a boss will appear. These bosses are made of several, multi-colored parts. And, remember, you deal more damage hitting stuff with shots of the same color. So, make use of that in your advantage! :)
Oh yeah, and all content is randomly generated. enemies, bosses and movement paths are all generated on-the-fly, so each time you play, the experience is unique :D