They do! I've found people, more than any other game i've made, do continue to send me messages regarding the game, or trying to improve upon their scores. I think the leaderboard is the main driver of that, I noticed a lot more of that when the leaderboard got added. Might just be the simple things, but I think score attack games live on competition - I did market research into Devil Daggers and talked to the community there, and a lot of them were driven by the leaderboard.