Yup, great game. It's been in development for a while, I think since 2009 (got the demo when it was called 'Hazard). Requires a lot of lateral thinking and it's so satisfying when you win.
Haha. There is a great sense of achievement, initially felt after doing the one with the the blue and red stairs. Kick yourself a lot, playing this, don't ya...
So we beat on, boats against the current, borne back ceaselessly into the past.