Bomb Jump
A Bomb Jump is when Samus gets hit in Morph Ball with a Morph Ball Bomb. Their main purpose is to propel Samus vertically while in Morph Ball. Most variations are rarely used outside of low% runs.
How Bomb Jumps Work
Metroid Prime 1
Bombs have a Bomb Counter whose initial value is 3 as well as a Bomb Refill Timer. When a Bomb is laid the counter decreases by 1 and the timer begins to count down from 3 seconds. The bomb that is laid can then be hit anywhere within this figure shown. Note this is slightly smaller than the full size of the bomb. This means Samus cannot get hit if she is too far below a bomb. The radius of this figure is .7 units, with Samus being unable to hit the bomb if she is located half the radius or .35 units below where the bomb was laid. Hitting a bomb gives samus a fixed vertical propulsion of just over 23.5 units. Underwater samus cannot bomb jump very well without the Gravity Suit. She is only giving a very tiny vertical propulsion of 8.7 units which is also quickly diminished because of water physics. While near the surface of water, Samus will "cling" to the water upon entering or exiting as the game switches physics suddenly. This can throw off timings of bomb jumps coming out of water. By laying a bomb and starting the Bomb Refill Timer, Samus can time a Bomb Jump so that the bomb counter refills during the bomb jump. This allows for Bomb Jumps of up to 5 bombs. Being able to continuously refill past 5 bombs is known as Infinite Bomb Jumping.
Metroid Prime 2
The refill timer was changed in echoes. TODO explain how new refill works
One Bomb In Air Rule
Starting from the Wii version of Metroid Prime and onwards, an additional rule was added that Samus cannot hit more than 1 bomb in the air a time. This was likely to prevent the player from doing mid-air Bomb Jumps using Spring Ball. One quirk of this is that some rooms such as Hydro Access Tunnel and Waste Disposal turn off this rule to allow the player to progress normally through underwater Morph Ball tunnels.
Unmorphing out of Bomb Jumps
By unmorphing out of a bomb jump at the end, Samus will continue to cary her speed and can use this to get extra height or distance from a bomb jump. Unmorphing too soon out of a bomb jump will cause Samus to lose speed and fall rapidly. Having Space Jump Boots increases Samus' vertical speed-cap which lets her unmorph higher as well. As a result some Bomb Jumps are only possible with Space Jump Boots.
Types of Bomb Jumps
Regular Bomb Jump Family
- Single Bomb Jump
- Two Bomb Jump (2BJ)
- Three Bomb Jump (3BJ)
- Double Bomb Jump (DBJ)
- Triple Bomb Jump (TBJ)
- Quadruple Bomb Jump (QBJ)
- Three Frame Bomb Jump (3FBJ)