Rocket Uppercut

Performing a rocket uppercut in Forbidden Jungle near the Fisherman.

A rocket uppercut is a movement technique that propels Jak vertically while maintaining a grounded state. The technique has applications in many speedrun categories and is one of the key components in Lava Tube Skip.

A rocket uppercut is performed by interrupting Jak's uppercut animation and maintaining the uppward momentum of the uppercut while returning to a grounded (or standing) state. This can be done by making brief contact with vertically oriented ground collision or by having a cutscene play during the uppercut animation.

Technical

Explanation

Some surfaces in the game are programmed to have ground collision for walking on, such as grass and wooden planks. While ground collision is intended for horizontal surfaces, it was sometimes mistakenly used when designing vertically oriented landscape details, such as the sides of a wooden plank. The wooden planks on the mine cart rails in Volcanic Crater are programmed with ground collision so Jak is able to walk on them, but every side of the wooden planks has ground collision assigned to it. This oversight allows Jak to perform rocket uppercuts off the sides of the wooden planks and to "walk" underneath the wooden planks by repeatedly pressing X.

Occurrences

• Cliffside Steps in Forbidden Jungle
• Wooden Rail Planks in Volcanic Crater
• Sandover Village Entrance to Fire Canyon
• Rock Pillar Platforms in Volcanic Crater
• Atop the Broken Sentinel in Sentinel Beach

Discovery

The rocket uppercut sometimes occurs during casual playthroughs so it is impossible to determine who first performed the trick. The first person to utilize a rocket uppercut in speedruns was Billbraid when performing an older variant of red sage cutscene skip.