There's still time to try "Schism", a game where you're uncontrollably shifting between dimensions! In the meantime, here's my usual analysis of what went right/wrong:

What Went Right

• Music: I don't think there's a time this is not going to top my post-mortem list. The dimensional shifts being on a 10-second cycle made it easy to make a set of simple 120 bpm 5-measure tracks. For both the normal world and the dark world, there are a total of 6 tracks, 3 of which are chosen from randomly from that world's set each time there's a shift. This helps alleviate some of the repetition, and create some interesting mixes of the various track (20 possible combinations). There is a stark contrast between the two styles of music (normal and dark) as well.
• Dark world visuals: The normal world is pretty basic; I made a tree in Unity, modeled a quick and ugly rock in Blender, made some textures for the grass and the trees, and it was done. For the dark world, besides the fleshy textures on the ground and trees, everything else was done using particles. The falling blood in the air, the wavy tentacle effects from the rocks... the one I was the most proud of was the tendrils coming out of the dark spirits that chase after you. The graphics in the normal world are nothing to sing about, but I really like how the dark world came out. The only thing I had to cut out was the tree tentacles; they were causing lag issues which in turn caused music to get out of sync, and the music was more important to me than the trees having tentacles.
• Adjustable map: I didn't end up using it, but I could easily change the radius of the playfield and the number of objects spawned, and everything was set up to accommodate whatever size I put in, including the placement of the wind barrier at the edge. The intent was to make it so that I could increase (or decrease) difficulty, but I never got around to using it. But the functionality was there.
• FPS movement: I didn't use any Unity plugins for the FPS movement, but scripted the mouse and keyboard movement myself. This is the first time I've done that, and I'm happy about it even if it doesn't mean much in the grand scheme of things.

What Went Wrong

• Flat land: Because everything was flat, it's nothing special to look at. The normal world could have had benefitted from some actual grass objects to make it look less plain, but when you're under a 48 hour time crunch...
• Extra enemies: I wanted at least one more enemy once you collected the second crystal, but there wasn't time to figure it out and put it in. What I probably would have made is something that moves slowly, but keeps teleporting itself into your path, making it much harder to run from the spirits. There just wasn't time though.
• Landmarks: The biggest feedback I've gotten so far is that people wish there were more landmarks to help them navigate better. In fact, I had made the trees move around on purpose just to try and make it harder to remember where you've been, and in retrospect that might not have been a good idea.
• Crystals: It's a bit too hard to find the crystals. I should have had something that would point you in the general direction of them if you were too far away, or increased the distance at which the pings started. In any case, it needed improvement.