I told his realtor (his realtor is representing both of us, i know big mistake) he failed to disclose that within the time contingency written on contract but hes saying "that would be hard to prove".I really don't mind walking away, but I've already paid for inspection and appraisal plus travel costs, time taken off work, etc.

Like @Nicolas Nuvan said having a good realtor is key for a number of reasons- beyond negotiating on your behalf and walking you through the buying process they can give you a realistic idea on rents in the area and usually can help you with drawing up leases (which I didn't do initially but that you definitely need to do if you want to build a portfolio). 

Walk from Point A to Point B.

can you walk me through your last deal? 

Doing a walk through this weekend, and will be presented the contract same day to be filled out.

Do not let auction ego get the better of you, it isn't a game, walk away when your line is crossed.  

During the initial walk thru a year ago, a comment was made regarding the door possibly not being "secure enough" that I ignored.

It’s about a 15min walk for me to get to the beach

Do a quick walk through the place BEFORE you show it to get an idea of what needs done. 

KNOW WHEN TO WALK AWAY BUT DON’T BE AFRAID TO PULL THE TRIGGER!