level123Brain Test: Level 123, How does this equation work ?Walkthrough Solution Of Tricky Puzzles. Brain Test is an addictive free tricky puzzle game with a seriesLevel 123: Rustwood Scrapyard Survival Difficulty: Class 5 »⠀Unsafe »⠀Unstable »⠀Entity Infestation Level 123 is the 124th floor of backrooms Description: Level 123 is a vast, desolate