Playing modern Windows games on Linux and SteamOS is done using Wine and Proton. Wine is available on almost every Linux distro and Proton comes* with Steam.
*You can use Proton outside of Steam but it’s quite hacky and not really needed.
It’s a dungeon management game from '97. You are an evil Keeper and control a dungeon where you need to build rooms and train your creatures to attack (or defend from) the good guys.
Nowadays people play KeeperFX which is the opensource remake.