I completed the game on the "normal" difficulty while completing the challenges, and then went back and beat every level for gold stars. I thought this would get me the hard badge, but it turned out I was missing one award. I clicked open the awards box to see what I was missing, and what was the last award?
"complete each stage three times"
...I'm sorry, but that's bull****. To get the award, I have to play through every level AGAIN, despite having done literally every possible thing in the game? I enjoyed this as a short, kind of simple time-waster, but not getting that award is leaving me with a sour taste in my mouth.
This is an amazing game, with a lot of potential. I'd love to see a multiplayer option added, and support for online play. This is a game I'd like to share!
 "Symbiosis"){kind=icon}
 "Steel Camels"){kind=icon}