isthereanydeal.com says it was bundled in a "pick any games for X" on reloaded.

That's a sale by Get Games.

another clue: has action elements

most recent clue

includes the letter A

Let's buy more vowels eh?? :P

I am hoping for Don't Starve; I will throw so much money at Groupees if it's Don't Starve.

Has Drox Operative been bundled before?

Ah, didn't notice that one.

Personally still think the most likely candidates are the Apogee Throwback Pack and Dark Matter (those guys must be desperate after the outrage over an incomplete game),

Er, why does it show luminosity when I click on mystery game? That doesn't have an "A" in the title.

edit: and Drox Operative has not been bundled before.

bug - I guess it is the next bonus game. Luminosity is also not on Steam, it is in the greenlight process.

Cool! Free ad for Luminosity, lol. It seems interesting, actually.

Also, Mousecraft, Savant Ascent, and Race the Sun.

Bonus unlocked aaaand Groupees has completely crashed out :/

Website is completely down :s Keeps popping on and off randomly

Should we contact the developers to resubmit theirs games to Groupees? *scnr*

Too much DRM. :/

Nah, is all fixed now
Theres a nice amount compared to most bundles still with three nice indie titles (Other than Humble, Groupees happens to be one of the only bundles to even consider DRM-Free versions of anything).

Its also worth noting that both Sang-Froid and Gun Metal can be run without steam, both of them still have to be downloaded via steam, but neither require steam to be up and about. Have yet to try the others

Another clue for mystery title - has trading cards.

Game will be revealed within next 48 hours.

Mousecraft, Race the Sun, and Drox Operative all have steam trading cards.

other maybes: WazHack (is it DRM-free?), Stick it to the Man, Steam World Dig (unlikely, I think), Octodad (unlikely).

The above games are DRM-free, and have been on Steam for less than 6 mo. Oh, also have steam cards.