Upgraded with the water freeze timer extension (EDIT: It's one of those middle path upgrades for skills and such.) it'll be a bit easier, still some of the later puzzles will be a bit difficult but as a side function of some other trainer option (Unsure which one.) the bar will refill instantly when you let go of the shift button.
This is also required for some of the puzzles but the easiest way to utilize this is to grab a frozen block or pillar of water and then jump away from it to the next, if needed let go of the shift button just as you jump and press it again immediately and the bar will be fully filled and you will still be able to grab the now frozen again water object.
(With the infinite rewind functionality you won't have to worry about failing either if you happen to miss a few times.)
(Some puzzles will still require very good timing and movement to manage towards the very end of the game but this should make them far easier to get trough.)
[Edited by LordJB, 6/12/2010 8:35:10 AM]
I went to Videogamesblogger.com and played the walkthroughs and in the later levels they freeze the power buttons with water and you have to hurry to get through the open doors.You can't let up on the shift key or the buttons will release and you have to start over.This is a slick programmers trick which makes the puzzle timer extention no good for these sequences.