UTAD via the side slingshots, ideally by going over either of the small rollover buttons.
Darling is the 2-player version of Jubilee, with the same central captive ball horseshoe and side slingshot design. What to do? Build your bonus, keep the ball alive; the points in the game other than bonus are trivial. Yawn. Bonus is earned by the top lanes (two when lit), by looping a captive ball to the opposite side, by the two small rollover buttons next to the bottom of the captive ball enclosure and by the outlanes. Bonus goes up to 20K. Bonus is doubled on last ball; double bonus cannot be earned on other balls. Because the game is so unbalanced towards bonus, you rarely see it in competition; a player with a big lead is all but impossible to catch.