Knytt Underground, normally priced at $15, is an exploration-based 2D platformer in which players solve environmental puzzles by swapping between their default humanoid form and a bouncy "ball" shape that can access hard-to-reach areas. Knytt Underground is available as a Cross-Buy title, and is playable on both the PlayStation 3 and PS Vita.
4A Games' first-person shooter Metro: Last Light, due for release tomorrow, is available to PlayStation Plus members for $48, or $12 off of its retail price. Codemasters' motorsports title GRID 2 also gets a discount ahead of its launch later this month, and PlayStation Plus members can pre-order it this week for $54.
Other free titles coming to PlayStation Plus this month include Pinball Arcade, Germinator, and BlazBlue: Continuum Shift Extend.