I really enjoyed the terrain mechanic in this game and how it ties into the double sided world. I didn't have too many problems, just noticed that the voice would restart mid sentence and I had one instance where my camera didn't flip after going to the other side.
I don't know if you plan on doing this, but I think there should be another indicator of radiation besides the voice, some sort of visual que.

the game is pretty cool. i like the idea of having different areas on the planet . I did find the game was a bit buggy and quite hard to find more than two zink and If you have time maybe check out my game also. Thanks