Velocity 2X: Critical Mass Edition PS4. CRITICAL MASS EDITION: Game, All Available DLC, Soundtrack CD, Studio Booklet, and Making of Documentary. Velocity 2X is a Sci-Fi platformer and shoot? em-up all-in-one adventure. This critically acclaimed sequel to Velocity Ultra weaves together two classic game formats into one seamless adventure, featuring puzzle-platforming action alongside award-winning top-down shoot? em-up gameplay.