Bomb Jump
Bombs can be used to propel Samus into the air. While slow, this technique is so robust that there are nearly no limitations to its explorative properties.
Bombs can be used to shift Samus both vertically and horizontally. Bombs can keep Samus airborne indefinitely and can even be used to propel Samus along ceilings.
When Samus's hitbox is caught by a bomb explosion, you will temporarily lose control over her. This lock happens when the bomb countdown timer reaches 9. If you become locked, you will have to wait until Samus's upward speed reaches zero after being propelled.
Tutorials
This tutorial is for a vertical infinite bomb jump that uses 3 bombs at a time to propel you up, to provide a backup compared with "double bomb jumping".
A tutorial for horizontal infinite bomb jumping:
Common Applications
Horizontal bomb jumps are commonly used to cross The Moat in Phantoon-first categories, as a slightly slower alternative to the Continuous Wall Jump. You can find an image tutorial from Sweetnumb here.
Vertical bomb jumps are commonly used in Any% PRKD to escape Draygon's chamber with a Blue Suit without Space Jump (in order to wall jump you would need to hold dash, which would cancel the Blue Suit). Using "ladder bomb jumping", this will be faster than a Gravity Jump.
Less Common Applications
Example of a series of horizontal bomb jumps:
Example of a series of ceiling bomb jumps:
When Samus's hitbox is caught by a bomb explosion while she is in the damaged pose (the pose that allows for damage boosting), she will be sent a direction in midair while maintaining the damaged pose, allowing for a damage boost to be performed after the effects of the bomb explosion subside.
The above has been utilized in nearly every recent inbounds tool assisted speedrun of Super Metroid as a way to pass through the bottom Kzan in Wasteland, including but not limited to Taco & Kriole's Any%, Cpadolf's 100%, and Namespoofer's 14% Speed.
