that's where I got stuck. I picked the gem and somehow moved the boulder, but could never really properly control it. Managed to do it once, but then the rock fell on me :)
Thanks for playing! That's so strange I've never hit and issue with controlling the boulder at all. Just to double check you're on the level with the green gem and once you've collected the gem and a new boulder spawns you can move it with the arrow keys?
If so can I ask if you're on pc or Mac? I'd love to try recreate this and get a fix sorted!