"We used to spend so much of our time on game play and today's games seem to
put too much emphasis on graphics and sound. It's the game play that makes a
game fun, sometimes they forget that." ~Larry Kaplan
Game play is a fairly ambiguous term from what I've seen. It describes the whole game experience excluding other means of describing the game such as graphics and sound. It can mean the way in which a gamer can interact with other elements in the game, and how enjoyable the overall experience is/was as a result.
One of the games I find myself playing a lot is Eternal Darkness on the Gamecube. Although it is not my favourite game, I keep coming back to it and getting friends that have never played it to try it out. The storyline is fairly detailed, each new level takes the knowledge from the previous and adds to it. You build up a repetoire of spells and techniques to tackle each enemy, and moving through the game feels like an actual progression that you don’t always find in other games.
The graphics in Eternal Darkness is not what makes 
it so enjoyable to play, it is the gameplay that makes it stand out from other games - the introduction of a sanity meter that not only messes with your character’s mind, but also the gamer themself.
SPOILER: There is a list of conditions you might find during low sanity can be found at - http://gameshelf.jmac.org/2008/09/eternal-darkness-sequel-highly.html
