Plasma Cannon 2 takes place in a specialized area within Prison Hall.
Plasma Cannon 2 is played entirely from a 2.5D side-scrolling perspective. In terms of layout, this extra stage is a straight path with several twists and turns.
The only obstacles encountered in Plasma Cannon 2 are the titular plasma cannons. These obstacles take the form of floating, gray balls with green holes in them. In gameplay, they spin around periodically, scattering green energy balls as they turn. Touching these energy balls will damage the playable character. However, the energy balls will disappear after hitting any surface, meaning the player can hide behind platforms and walls to dodge them.
When Plasma Cannon 2 begins, the player has to get through a long corridor that has several plasma cannons and bottomless pits along it. After passing the first Star Post, the player then has to climb a ledge with two plasma cannons around it. Once at the top of said ledge, the player has to continue in the rightward direction. Along that way, the player has to go up and down a few shafts that are positioned above a bottomless pit and have plasma cannons inside of them.
When the player gets back on solid ground, they have to pass this extra stage's third Star post. The player then has to make it through a room with three closely-packed plasma cannons. After exiting this room, the player then has to cross a section with small platforms over a bottomless pit while plasma cannons rain down shots from above. Should the player make it past this section, they will have a clear path leading to the goal.