Power Beam
From A complete guide to Super Metroid speedrunning
Power Beam is Samus's standard beam, which she has at the start of the game. It only deals 20 damage, but receives many upgrades during the game to bolster its damage and utility.
Without the Charge Beam, holding the shot button down causes two shots to be emitted approximately 15 frames apart, and all shots thereafter to be emitted approximately 25 frames apart. Tapping the shot button repeatedly allows you to fire at a faster rate than if you held it down, with a cooldown rate of 15 frames.
The rhythm of the shots when held down is used for certain strats, such as the most common strats in Terminator, and certain setups for Out of Bounds movement.
