After bidding up the purchase of our home above asking price in
Chicago, we chose one of the two buyers. Near the end of the 5th day of attorney
review, he sent an attorney letter asking for a few things, including
5k back for working items and the ability to pull out a week before
closing. I emailed him asking him a few questions,
then the next day he sent another letter through his attorney pulling
out of the deal. I feel he was not in good faith and likely never
planned to follow-through at that high price. We lost the other high
bidder since she was soured by the bidding. We ended up selling at 30k
less. Is there any worth to a civil lawsuit to recover this
difference? I have more information, if needed, such as his delays,
failure to communicate, and cancelling his earnest money check. I hear
that you can pull out for whatever reason during attorney review, but
he pulled out without even my response through my lawyer.

He cancelled the earnest money? You mean stopped payment? Pretty
serious stuff, but pursuing a claim for loss is gonna be expensive.
Why not try a small claims action for the legal limit in your area (up
to $10000, with some restrictions).

Well, it's unfortunate you already sold the house at a loss.  You
could have sued for "specific performance", that is, ask the court to
force the deal to go forward.  I'm assuming, of course, that the facts
support your case.  I could be wrong.

It all depends on what your contract says.  First, the earnest money
deposit should have been deposited at once.  As for the attorney
review, that was an open ended contingentcy.  And the five day review
was long and pulling out a week before closing - unheard of.  You
should have also taken a back-up contract from the second buyer.  You
don't say so, but I would bet you sold the house yourself and did not
use a real estate agent.  You didn't "lose" any money because you
really did not have a serious buyer at that price.  It all boils down
to what your contract says.  If the buyer pulled out under the terms
of the contract you have no recourse.  If he violated the contract you
can enforce it in court.