You can no longer buy it directly. Remaining Steam keys are extremely rare and expensive, often listed between $121.82 and $532.93 on sites like DLCompare and K4G.COM .
Contrary to many "free download" claims, . It was a paid digital title that has since been delisted from major platforms:
Supports up to four players online in a "co-opetition" mode where you work together to survive but compete for the most "nuts" (currency).
It was removed from Steam, Xbox Live Arcade, and PlayStation Network in 2017.
It was briefly free for Xbox users via "Games with Gold" in December 2013, but that offer has long expired. Key Features