first impression: concept: awesome.
second impression (at 6/10): very clever. so far you haven't gone beyond implications, biconditionals (iff) and conjunctions/disjunctions. going much beyond that would be pretty far beyond the capability of your average gamer and i assume you want people to at least try to finish this and in a reasonable % of cases, succeed, so that was wise on your part.
third impression (at 9/10): still fun. i wasn't sure what a red herring was, but i still completed the puzzle. i think maybe you should have defined what a red herring was. it was obvious to me from the context, but it may not be to some others and that may stop them from completing the game.
fourth impression (at 10/10): i've never seen the underscores under the and/or symbols before. it wasn't necessary. was it just to make things look more complicated than they really were? 10/10 was one of the easiest puzzles in the game.
final impression: wasn't too pleased with the ending.
was still fun and a definite 5/5