Was always a fan of puzzles, and had a lot of fun figuring out those "impossible" ones in time. A nice variety of puzzle types and difficulty.
I found a "bug" though. If you skip a puzzle, it doesn't count as one of the 25, so you could skip all the easy/meds/hard to get a bunch of impossible puzzles and get a really high score.
So I decided to try that, and i found yet an other bug. There are only 2 impossible puzzles, so i eventually got to the end of the list of puzzles. Once you get there, solving or skipping the "last" puzzle would just give you the same puzzle over and over. So you could find the answer to that puzzle then spam type it in 25 times for an easy high score.