Mega Man 5
General Techniques
MM5 - Charging the Buster
The Mega Buster will not charge while sliding in this game. As such, many times when a top runner is walking and charging, they did not miss a slide but instead are actively building a charge shot.
How Beat Tracks
Beat will attack an enemy if Mega Man is motionless. This is usually on the ground, but also happens at the peak of a jump if you are not moving left or right. You can use this to make Beat attach while jumping over Dark Man's shields, or to be faster to attack Wily Capsule.
All About The Super Arrow
The Super arrow takes two points of ammo to fire, though it can be fired with only 1 point of weapon energy remaining.
You cannot walk (or slide) off the front of a moving arrow - it will catch you.
Riding the Super Arrow drains 1 point of energy as Mega Man is on it. As such, many strats in this game walk off the front of the arrow, reducing the time Mega Man is technically still riding it, and conserving "just enough" ammo.
You can stand on an arrow stuck to a wall until it despawns without draining ammo.
Crystal Man
The Crystal Skip
The Crystal Skip saves a good amount of time over completing Crystal Man's stage, at the cost of not being able to collect the M tank or the Beat Letter within. As such, it is only useful if you intend to complete Castle stages (and bosses) without Beat, or you are in a no Castle Stages scenario (such as 46 Robots).
This strategy involves an intentional death, so make sure you have an extra life, even if it is Mega Man 5
Note the ball enemies do 3 points of damage, so Mega Man should have 1 HP remaining before taking the intentional death.
Arrow Setup
clear the 2nd and 3rd enemies after getting Mega Man to 1 HP remaining, then equip Super Arrow. You need 3 arrows.
From a standing position, fire one arrow to the right. Quickly jump on it, then fire an arrow left. Quickly jump on THAT, and fire a third arrow right. Stand on the leading tip of the arrow.
Mega Man should take a death, and the NEXT ball enemy should be missing its top half. Your respawn will take a very long time, but you teleport into the boss corridor.
Arrowless
What Even Happens?
This strategy kills Mega Man on the same frame another enemy spawns. This produces too many sprites for the NES to handle, overflowing the array of sprites on screen. Some of the data gets written into memory dedicated to Mega Man's X coordinate in tehestage, and the time until respawn. This sets Mega Man's position past the final checkpoint (in the boss corridor), making him respawn there. It also makes the respawn timer...large...so you have a moment to get a drink here.