Unlimited Double-Up app for iPhone and iPad

Shoot for the millions with "Unlimited Double-Up"

"Double-Up" is like a casino video poker game, where you can play as much as you want for free.
In "Double Up" the player guesses whether the card shown face-down on the right, is greater than, less than or the same value, as the card shown face up on the left.

You start with $1, and if you win, you can double your money to $2.
At this point, if you press the "Payout" button, your score will be recorded, but if you press the "Double-Up" button, you can try to double your money again.
But if you’re not able to double-up," then you will lose all of your winnings up to that point, and your score will not be recorded.
Double-up until the last minute, and shoot for the big payout!

Also, as you continue to win and keep doubling-up, the odds of winning change, and the lower the probability you choose, the higher the odds you get.
Should you go for the big odds? Can you double-up for sure?
Devise your own to become the No.1 Double-Up player in the word!