There are three achievements I'm unable to gain:
1.) Zehn Moment - I'm definitely finishing the level in time, but no achievement
2.) Mind: Path to Amsterdam - I'm completing the puzzle, but no achievement
3.) Hidden area & associated achievements - as described elsewhere, I enter the left elevator, teleport to the Antelope, but from the gateway I either go straight to the level menu or I arrive at the hidden level but fall through.

I'm assuming these are bugs. Anyone know differently?