Powerup

Overview
Powerups are an item dropped by Boxes. They give certain effects depending on the powerup;

Freeze
Depicted by an ice crystal, or an ice cube on the mobile version, this powerup freezes solid all enemies and spawners  for about 5 seconds, allowing you to move near them and shoot at them without response from them.

Invisibility (mobile only)
Depicted by an eye with a line through it, this powerup makes you invisible to all enemies for about 5 seconds, allowing you to move around and shoot enemies without being seen; however unlike ice cube enemies will still move around and react being shot, though they won't attack you.

Radar (mobile only)
Depicted by a satalite, this powerup removes all fog of war on the stage, allowing you to see everywhere; expecially useful on large stages and if you use the Binoculars to see further after picking it up. This effect is permanent.

Damage boost (mobile only)
Depicted by an orange fist, this powerup increases your damage for about 5 seconds, giving roughly 2x damage bonus.