Octopus City Blues is a game founded by Kickstarter, but someone managed to get a hold of the game and uploaded seven playable levels and published it on Steam. The one described in this page is the malicious Steam game, which disguises itself as the legitimate game.
Due to Steam's lack of quality control, there are malicious games in the store, and the developers of the real game have tweeted about the game.
When game is installed and run, it attempts to steal the user's Steam account credentials. The theft can be avoided by turning on Steam Guard.
Nathan Grayson, Warning: Scammers Are Hiding Malware Behind Fake Steam Pages. 2015.07.04
William Fieldhouse, Malware Hidden In Fake Steam Pages – Scam. 2015.08.04