actually i didn't realize the dino can duck until i was grabbing the sound effects from the original, i think i just sucked at dino so i never could get to the part it's actually used in
I didn't realize for a long time either. I think it can't duck on mobile or so.
Ducking will also make you fall faster, so it's useful through the whole game. I may have played too much of the dinosaur game.
