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Ferry people across before the two minutes are up. The water pushes you sideways, so point the nose upstream or you will drift straight past the jetty.
The stick points the NOSE of the punt, and how far you push it is the engine. Let go and you float along with the river.
Three lines are drawn on the water. The dotted dark one is where the nose is pointing, the dotted blue one is the river's push where you are right now, and the red one with the arrowhead is the two added together — where you are actually going. Put the red one on the jetty you want. Aim straight upstream in the middle of the river and it shrinks to a ring: that is you holding still against the water.
Somebody waiting holds a little sign saying which jetty they want. Touch their jetty to pick them up — the punt takes four — and touch the one on their sign to drop them off. A landmark that bounces is one of your passengers wanting to get off there.
The river is slow at the banks and fast down the middle, and it speeds up as your two minutes go on. Going UP the river costs about three times as long as the same trip coming down, so which fare you take next is most of the game.
On a computer: ◀ ▶ swing the nose, ▲ is the engine, and space starts a run.