A vertical shoot-'em-up built on charge, you and every bullet are light or dark, you absorb your own colour, and the opposite kills.
Your ship carries a polarity, light or dark, and so does every incoming bullet. Bullets that match your charge are harmlessly absorbed and stored, while bullets of the opposite charge destroy you. Your own shots deal double damage to the opposite colour, and you can flip polarity at will to survive shifting waves, then unleash a stored charge to clear the screen.
A vertical shoot-'em-up built on charge: you and every bullet are either light or dark, and you absorb your own colour instead of dying to it.
That polarity mechanic is not ours — Treasure's Ikaruga made it famous in 2001 — and this is an original game working in the same tradition rather than a copy of it.
What the idea buys is a reason to fly into fire. Ordinary bullet-dodging is entirely avoidance; when half the screen is nourishment, the optimal path runs through the danger, and switching colour at the right moment matters more than finding a gap.
Polarity is an original free browser game in the bullet-hell shoot-'em-up genre, built around a two-colour charge system where absorbing and reflecting matched fire is the heart of survival.