Double Bomb Jump
A double bomb jump (DBJ) is a type of bomb jump. It gets double the height of a normal bomb jump. The double bomb jump is actually one of the only bomb jumps which is intended by developers, as it is required in a few puzzles and shown in some of the attract demos. There are two main types: a regular double bomb jump which goes straight up, and a "laddered" Double Bomb Jump.
To perform a double bomb jump, place a bomb on the ground where you are. Shortly before it explodes (a visual cue is almost immediately after the bomb animation disappears completely before exploding), lay another one.
At the peak of your jump, but before you start descending, lay your final bomb. The second one you laid will boost you up, and then the final one you laid will hit you in midair.
Laddered Double Bomb Jump
To performed a laddered double bomb jump, do this process, but add some lateral movement into it. A basic explanation of inputs is holding the control stick forward slightly before the first bomb explodes, and then holding back after you place the final one and keep holding back for a short moment after landing. Once landed, roll backward a short distance and then roll forward (or in whatever direction you were jumping toward) as much as possible to hit the second bomb you placed. Keep holding forward the rest of the jump.
Double Bomb Jumps are also prevalent and required in normal gameplay in Echoes, but can also be used to traverse many rooms without the Space Jump Boots.
Just like the previous two games, DBJs are used in Corruption, though to a lesser extent. Bomb Jumps in this game can be replaced with Spring Ball. For a Double Bomb Jump, flick the Wii Remote upwards to use Spring Ball and lay a Bomb at the peak, then use Spring Ball again before the Bomb explodes to gain the extra height from the bomb.