Alright, first off, I GOT IT IN THE END! YES!
Now then, to the actual critique. It's been years since I'd done a puzzle like that, but that didn't change the sheer enjoyment I got out of this. I've played a few other tickle games where you're working toward the goal of seeing some tickling, but this is perhaps the most well done that I've seen. The puzzle was tough, but not so impossible that I wanted to quit. Just enough that I wanted to press on (cause I'd already worked so hard, consarn it!). Then seeing the message confirming I'd won...yay.
Which brings me to my final point. The prize is so worth it. Very well done. I won't spoil it beyond that for those who might read this hoping for some spoilers
Overall, a very fun and original game. Four thumbs up!