From the Twitter account of MonkeyPaw Games …

BurgerTime World Tour got a notice the liscense is expiring. On April 30 it will be taken down for sale. Should still be able to DL purchase

As a result, we dropped the price to $4.99 until April 30th. Snack on BurgerTime while you still can

Unfortunately the price drop only applies to other versions, as the WiiWare one is still selling for 1,000 points.  Still, if you’d like the play the game (and don’t have another means) grab it before it vanishes at the end of the month.