“Games are better if they hold up to competitive play, but they MUST hold up to non-competitive play. Don’t allow your game to drag on or fall apart if players don’t pursue victory as aggressively as you expected them to.”
— Seth Jaffee
“Don’t automatically conflate a game’s set-up variability with its replayability. After all, based on centuries of evidence, Go and Chess are the most replayable board games. Instead realize that a game’s replayability often results from the variability within its players.”
— W. Eric Martin
“Ideas are a dime a dozen & mean nothing if the work isn’t put in to actually make a game out of it.”
— Jason Dinger

Lots of advice for pitching to publishers, plus answers to questions about playtesting and the game design process (video)

How to let go in game design: identifying and eliminating bloat from your game (video)

T.C. Petty III discusses board game development and how developers work with designers (video)

“I see over a thousand game concepts every year and you must make yours stand out. What’s most important is the game itself; the exciting new game play or game mechanism. So, show me a prototype that brings this to life!”
— Tanya Thompson, Hasbro's head of acquisition for games