I like it, that I can spend and regain upgrade points all the time and that you made it part of the puzzle. This was really interesting. Sadfully I realized later, that I accidently cheated myself through the game, because setting the dry steps lower or higher sets the system value onto exact that value. So you can make dry steps, lower and raise the upgrade of dry steps and you have regained dry steps while standing on a sand bank.
But in general its really cool.