Me suspects you're just a bit rubbish at Slitherlink
I just finished this with a total time of 58 hours or so, which is a lot quicker than I suspected it'd taken, weirdly. There are some right bitches in that final set of puzzles. 40 being one of them, but 47 being the devil. Took me two attempts at 90 minutes plus each to get that one done, and had to work out some strategies specifically for that puzzle, it was that tough.
As for the original topic, 10/10? Nah, not for me. There's a couple of problems that'd knock it down a point - slowdown being the main one. The last thing I expected in this game, and it makes the latter stages of huge puzzles awkward. It'd have been nice if when you were working on a line it was highligted a different colour on the top screen too. The top screen is next to useless.
God knows what I'm gonna play for my puzzle fix now.