GRAIL was the entry for my first Ludum Dare 48h competition. The theme was "You Only Get One". My take on this was to give the player only one button to complete the game. This was a further exploration into the possibilities of one button controls.
Since it would be a very short game, I wanted to confront the player with a challange. I think I succeded in this by cranking up the difficulty at some point in the game, although some players complained about trail-and-error and a somewhat punishing distribution of checkpoints. Honestly, these are flaws I cannot argue away. I still hope that the majority of players would enjoy GRAIL as what it is: a minimalistic game you can only beat with patience.