Atomic is a Multiplayer level. There is no in-game name for this level, the name comes from documentation included with the file.

Spawn Locations

• Top of double-raised ramps near Castle Structure.
• Alcove beside Castle Structure, opposite side from Biosuit.
• Central structure of Middle Section.
• Across from Green Armor in Largest Section.
• Roof, intersection between roof, upper floor of Castle Structure, and corridor access by extending Bridge in Largest Section.
• Largest Section, corridor between two 25 Health and Elevator to Castle Structure.
• Largest Section, opposite side of Super Nailgun corridor, main portion.
• Largest Section, top of ramp in corridor beside outer wall opposite Elevator to Castle Structure.

Important Item Locations

Weapons

• Double-Barrelled Shotgun - Top of double-raised ramps near Castle Structure.
• Double-Barrelled Shotgun - Roof, intersection between roof, upper floor of Castle Structure, and corridor access by extending Bridge in Largest Section.
• Nailgun - Largest Section, dead-end corridor under Thunderbolt corridor.
• Super Nailgun - Largest Section, corridor between two 25 Health and Elevator to Castle Structure.
• Super Nailgun - Middle Section, upper floor alcove near central structure.
• Grenade Launcher - Central structure of Middle Section.
• Rocket Launcher - Alcove across from central ramp of Largest Section.
• Thunderbolt - Largest Section, top of ramp in corridor beside outer wall opposite Elevator to Castle Structure.

Powerups

• Quad Damage - Middle of Corridor With Railings above Castle Structure.
• Biosuit - Slime beside Castle Structure, first floor.
• Green Armor - Alcove beside Castle Structure, opposite side from Biosuit.
• Green Armor - Largest Section, corridor of lower floor beside Rocket Launcher alcove.

Room-By-Room Summarization

Castle Structure

• Quad Damage in middle of Corridor With Railings above castle.
• Biosuit in Slime beside castle, first floor.
• Green Armor in alcove beside castle, opposite side from Biosuit.
• Double-Barrelled Shotgun at top of double-raised ramps.
• Shells at top of double-raised ramps.
• 25 Health at middle of first floor corridor beside castle.
• Slime can be found along the edges of most corridors, but only the area near the Biosuit is accessible in the main corridors.
• Castle itself contains another pool of Slime.
• Elevator on Biosuit side corridor leads to upper floor of castle.
• Shootable Button on upper floor, Green Armor side, that lowers Quad Damage Corridor into the pit of Slime held by the castle.

Middle Section

• Grenade Launcher in central structure.
• Super Nailgun in upper floor alcove near central structure.
• Nails in upper floor alcove near central structure.
• 2 Rockets in central structure.
• Elevator on Biosuit side leads from first to second floor of central structure.

Largest Section

• Green Armor in corridor of lower floor beside Rocket Launcher alcove.
• Nailgun in dead-end corridor under Thunderbolt corridor.
• Super Nailgun in corridor between two 25 Health and Elevator to Castle Structure.
• Rocket Launcher in alcove across from central ramp.
• Thunderbolt at top of ramp in corridor beside outer wall opposite Elevator to Castle Structure.
• 2 Nails in dead-end corridor under Thunderbolt corridor.
• 2 Rockets in alcove across from central ramp.
• 3 Cells at top of ramp in corridor beside outer wall opposite Elevator to Castle Structure.
• Two 25 Health in corridor nearest Middle Section.
• 25 Health at base of ramp in corridor beside outer wall opposite Elevator to Castle Structure.
• 25 Health at top of ramp near middle of room.
• Elevator in middle of section leads from first to second floor.
• Slime can be found along the edges of most corridors, but only the area under the ramp leading to the second floor and beside the bars looking into the Nailgun area are accessible.
• Shootable Button on upper floor corridor, by section overlooking corridor beside Middle Section, causes a Bridge in the corridor to extend to allow access to the latter corridor.

Roof

• Double-Barrelled Shotgun at intersection between roof, upper floor of Castle Structure, and corridor access by extending Bridge in Largest Section.
• Shells at intersection between roof, upper floor of Castle Structure, and corridor access by extending Bridge in Largest Section.
• Two 25 Health on roof.