I'm not very familiar with making games in 3D, but I have used Macromedia/Adobe Flash for quite some time now, which is used to make 2D animations and games. So I'd like to see if you can create something that works for the Rift.
Another thing to mention is that you can run a flash on anything really, so you don't need a particularly good computer.
I don't have my Rift yet so if you could try a few things, then that would be highly appreciated.
The number in the bottom left corner is supposed to be the PD, but all it really is, is a variable that tells how many pixels apart the objects should be on the screens. Then that is divided by another variable which is bigger if it is supposed to be far away.
What I would like to know is if the red ball appear to be close and if the mountains appear to be far away, if so, how close and far away. Also what your PD is, and what you set the number to, so that I can make it more accurate. If there aren't enough to look at in order to make a judgement, please let me know.
All you need other than the main file, is holophone3d's overlay which distorts the screen, which can be found on the middle of the page here: viewtopic.php?f=29&t=299
To open the file, just right click and open with any web browser. Oculus Rift Test.rar
Ok, I just tried it. The number I used was "-24". Looks OK, not great.
Really, you probably want to be rendering in true 3D, even if you still use 2D sprites (i.e. billboards). The latest version of Flash can do hardware accelerated 3D, and there are libraries that help with this (like Away3D). It may be worth looking into.
If you do build a 2D game, it would not be a completely dumb idea, but..
You will need to bulge the screens on each side of the view plane, and render the content on each side.
You can adjust the displacement of the shapes, with 0 displacement appearing far away and, some maximum displacement appearing close to the eye. It should produce an effect of flat objects at varying distances (Similar to most of the effects coming out of 3D movies).
Those effects would make the 2D game interesting playable. The absence of those effects would not fully utilize th capabilities of the rift.
You are better going for something like a 3D side-scrolling or 2 1/2 D game.