this game is playable in Linux (possibly on Mac OS too) if you can get Steam game files from Windows machine. Just login on friends Windows machine to your account, download the game, find and copy its files to your Linux/Mac machine and start it with Dosbox. Easy.
The question is - why we have to download it elsewhere? Can't someone (Valve?) add to Mac/Linux requirements "Dosbox installed" and just let us download on other OS too?