I've been giving the Tidalis demo (1.000) a try. I was enjoying the brainteasers, but as they increased in complexity (at 5-3 now) I found it more and more irritating that it wasn't possible to tweak my previous solution, and would have to start from scratch each time.
Currently the best I can do is screenshot the solution before hitting the button, but that still means I have to painstakingly set everything back up again using that picture as a reference, before then making whatever tweak I want to try. After the 2nd or 3rd time this is no longer fun, and I'm now quite likely to just abandon it. It takes too long to try each idea.
I thought a quick save system would solve the problem, so you could save just before hitting the button, then reload if it didn't go as planned, but if there are other solutions I haven't considered then please let me know.