Grab the orb, and the secret is marked as found. You can now finish the level normally.

The 4-2 secret is located in the game's fourth level, " Industrial Complex". To access the secret, players must navigate through a specific sequence of actions, which involves exploiting a seemingly innocuous wall in the level. Upon activation, a hidden door swings open, revealing a secret area filled with enemies, ammo, and health.

Entering the portal transports you to a unique arena that pays homage to the "Cybergrind" but with a twist. This secret mission is a test of endurance and mobility.

In conclusion, the 4-2 secret in ULTRAKILL is a hidden gem that adds depth and replayability to the game. Its design and gameplay mechanics are carefully crafted to provide an intense and challenging experience, while also showcasing the game's emphasis on exploration and discovery. As the game continues to evolve, it will be interesting to see how players and developers alike continue to interact with and build upon the secrets and areas hidden within.