If you are looking for a free alternative, there are many fan-made Backrooms projects on that are legitimately free to play and safe to download.
The core of the game is the 4-player co-op. "Cracked" versions usually cannot connect to official servers, leaving you to play alone in the dark. How to Get the Game Safely: Inside the Backrooms Free Download (v0.1.9a)
Version v0.1.9a is quite old. The game has received numerous updates with new levels (like the Sewerage and Rooms), new entities, and crucial bug fixes that pirated versions lack. If you are looking for a free alternative,
However, it is important to note that is a paid title developed by MrHeartbeat. While you might see links for a "Free Download (v0.1.9a)," these are often unofficial and carry significant risks. Why Avoid "Free Download" Sites: How to Get the Game Safely: Version v0
The best way to play is through . It is regularly updated, supports full multiplayer, and often goes on sale for a very low price (usually around $5 USD). The v0.1.9a Update specifically added: New puzzles and "Level Fun." Improved entity AI. Optimization fixes for better frame rates.
Unofficial downloads are the primary way malware, ransomware, and miners get onto computers.
It sounds like you're looking for information on how to get your hands on . This game is a popular co-op horror experience that captures the eerie "liminal space" aesthetic of the famous internet creepypasta.