Tip: chips stay with you between runs. Spend them in the Foundry for permanent boosts.
Suggested upgrades:
Your tower stands in the middle and shoots the nearest enemy by itself. Enemies come from every side, in waves that keep getting stronger.
Destroyed enemies burst into pixels. Spend pixels on the upgrades under the game: damage, fire rate, range, tower HP and the pixel absorber (armor).
Tap the screen, the NOVA button or Space to blast every enemy on screen. It takes a while to recharge, so save it for emergencies.
Each cleared wave also gives pixel chips. Chips stay between runs: spend them in the Foundry for permanent boosts.
Pause with the Pause button, P or Esc.
Highlighted rows set a new best wave.
Pixel chips come from clearing waves: 1 per wave, plus 1 more for every 5 waves reached. Spend them here on permanent boosts that carry into every future run.