Here's a question for discussion...

When i buy a chess puzzle book, i have to plan & play the moves for both sides.  And you don't check the answer until you're sure you solved it (or at least you thought you had solved it). after all, once you see the answer, you have to move onto the next puzzle anyway. 

At this site, the opponent responds to your move, and if your move is not the right one... it returns to its spot and that move is ruled out of the possibilities.

if chess puzzles used the same programming as the new conditional moves features (i.e. you need to enter all the moves to solve a puzzle at once for both sides, before you are confirmed/rejected), i would expect that:

1) the puzzles would become significantly "harder" or even impossible.

2) people would be turned off and not check in for their daily puzzle fix.

i suppose there could be an easy/hard toggle for doing daily puzzles in our settings with default on easy. the hard setting would probably have to display the total number of moves to solve.

Maybe a little complicated on the Erik side of things... but yes, a fantastic idea.