I hope you can find someone who hasn't played the multiplayer before! Doing it with someone who knows how to do the puzzles would kill most of the fun, I'd imagine.
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No amount of planning will ever replace dumb luck.
Yeah I was really itching to play the co-op again, but I've beaten it all already. Months and months ago, but still. There are some really unique solutions that are really great for the first time.