The Indie Royale series continued on this week with The Sigma Bundle, a seven-game offering that comes with a question: What's in the box the mystery game? We won't know until it's revealed on the bundle's page, but what we doknow is that the seven-game pack currently includes a first-person shooter, space simulator, real-time strategy game, two platformers and tactical and first-person RPGs.

The entirety of The Sigma Bundle is compatible with Windows platforms, but only Gravi, Skyward Collapse, 3089, Survive, and Freedom Fall are available DRM-free. Starpoint Gemini and Starvoid come only in the form of keys for Steam or Desura. Mac users will be able to play Gravi, Skyward Collapse, 3089and Freedom Fall, while Linux fans can have Gravi and 3089.

If your interest is peaked, the minimum price at the time of this writing is just under $6, with n00bstar's "operat0r" album thrown in if you pay $7 or more. Trailers for most of The Sigma Bundle's contents can be viewed by clicking the box art for each game on the offer's website.