This challenge takes its roots from when I first downloaded the trial version. Not knowing much about the game, I jumped right in to Alternative mode, not realizing I was missing the tutorial. When I came across the first level with a machine on it, namely level 6 of Harara Mountains, I assumed that the strange green circle was a collectable. I couldn't figure out how to collect it, so I skipped over it. It was only when I got completely stuck on a level in Old Ruins that I played the Normal version and figured out that I could activate those things.
The Challenge: Complete Harara Mountains and Skymning without pressing ENTER.