I like that puzzle too!
2 vs 5
Yes, a solution "seen" without calculating all the way to the end is certainly not a true solution. However, what I'm saying is that it's not very fun to have such a solution, because it takes less time to figure out the entire puzzle than in the case of a non-obvious first move.
One thing about puzzles here is that when you make good move it you get OK msg, and you can continue the line. If I posted this puzzle as a diagram, does first move still look natural? If there is not that kind of help, you would have to play to the end of all variations to see where you end up.
Personally I never make my move on the board until I'm sure I have a solution. So that's not really an issue for me.

@ NuclearTurkey
Thing is in this situation, b5 is the natural and obvious move. People would go here and just move it straight away (if they're good enough that is, and you don't have to be very clever either). Why? Because it IS a puzzle, and it locks the king away etc and there is no other move. If there was a real game, then analyse would be done (little in this case though).
NP, hope I can post more soon.