How to play

Your T-Rex runs on its own and keeps getting faster. Jump over the cacti and duck under the birds. Don't hit anything.

Reach the target score shown up top and the cache is revealed. Crash before then and you can try again with a fresh run.

Want a challenge? Tick "Keep playing past the goal" to carry on after you reach the target and see how far you can get. You still have to reach the goal to win, but your result is held back until you crash.

On a keyboard: Space or the up arrow jumps, hold the down arrow to duck. On a phone, use the Jump and Duck buttons, or tap the game to jump.

Vibration is off until you turn it on, with the small button above the game. What it does depends on the phone. On an Android phone your tap gets a short buzz. On an iPhone or iPad you feel your own tap and nothing else, because that is the only thing iOS lets a web page do.