It's a box, so Half Life Orange Box! it's gotta be a dead cert :P

Minecraft finally coming to GOG. ;)

Q*bert. Yeah, not going to happen but I'll guess it anyway. :P

The lighting on that cube seems wrong. The darker face is actually exposed if you look at the shadow. Furthermore, it's purple.

All this leads me to believe that we have Day Of The Tentacle inbound!

Yeah, not even going to try to work that one.

My guess is a bit convoluted but it fits: Zak McKracken and the Alien Mindbenders.

The artist John McCracken made a pink cube that looks like the one in the hint, look.

Cube & Star: An Arbitrary Love ?

Cube.. game.. Gamecube.. Nintendo confirmed!?

Antichamber?

You have a quick understanding of blue enigmas.

If it is Q.U.B.E. that did look like an interesting game! Here is the MobyGames page.

If there were a finished PC version imminent I'd say Godus, because of what was inside the cube.

As it is... Endorfun, perhaps?

I believe there is a cat inside... So a game with cats? :P

Gamecube Resident Evil Remake? I read something somewhere that there are some plans for doing it, but I think it was scheduled for 2015...

A DRM-free version of 3ds Max!
I knew GOG would eventually announce their plans to expand beyond gaming. Thank you so much, Judas! :P