Requesting Player Feedback!

I'm working on a Time Limit feature for WAR Card Game_uvr before I work on the Achievements. I'm trying to shorten the game to a more reasonable length since it usually goes on for an hour or so or longer until the cards finally play out and there's a winner. It would work in the following way: The player would enable the feature by clicking a checkbox (on the Start Panel) which would enable an input field (also on the Start Panel) into which the player would type a number of minutes (currently ten minutes minimum) then start the game. The game clock would count down the game time remaining until the time limit is reached at which time whichever player is leading would be declared the winner. If there is a tie, the game is declared a draw. I would like player's and potential player's feedback on what they think should be the minimum time limit as well as how they think I should handle potential stalling on the part of the player. The player could easily win just by playing a few rounds until he or she is ahead and then just wait for the rest of the ten minutes to pass and win.

I would also like feedback on what kind of reward(s) you think players should get for playing the game without the time limit and winning. I believe they should get some sort of longevity achievement award. What do you think? Please enter the discussion here or email me at wardevjack@gmail.com. I would greatly appreciate it. Thank you.