Amazon for no more than $9.99. The bundle contains both Prototype and Prototype 2, the latter released earlier this year. Frankly, ten bucks would be a surprisingly low price for the sequel on its own, let alone bundled with the first game.
Prototype hasn't been a popular series at retail, with lackluster sales contributing to "significant" layoffs at developer Radical Entertainment. While Richard felt Prototype 2 has far too much inanity in its plot, his review shows he still enjoyed its destructive qualities.