I’m (somewhat) in!
I’m doing this! Sadly I work for much of the weekend, but that will just make me think through my plans a little more thoroughly.
For this jam I plan to use either Game Maker:Studio, or Unity. I would prefer to use Unity if I think that I can, due to GMK being a bit awkward in places, and so that I could have a web version, but I’m still not very skilled with Unity, so I’m still on the fence. I’ve been spending the last week trying to put things together in Unity to make it more of an option.
And of course, GIMP and/or ASEPRITE, and sfxr, because both are free and wonderful. I’ll be generally holding to the compo rules, and I would like to submit for that, but if I don’t like what I have by then I may just call it a Jam entry. Time will tell.

