Round 1, the point builder. Sixty seconds of fast questions. Every right answer banks 2,000 points, and three right in a row adds a bonus. A wrong answer costs nothing but time.

Round 2, the offers. The Strain puts three deals on the table. Take the big one and you start one rung from its grasp. Take the safe one and you start three rungs clear, for far fewer points.

Round 3, the head to head. Eight rungs. You answer, then the Strain answers the same question. A right answer moves that player down one rung. Reach home and the points are still in play. Get caught and the round is over.

Round 4, the final chase. You get ninety seconds to stack up rungs, then the Strain gets ninety seconds to run them down. Each time it slips you get one shot to push it back a rung.

Controls. Click an answer or press 1, 2, 3 or 4. A short reason prints after every answer, so read it before you move on.