У вашего броузера проблема в совместимости с HTML5
Instructions: https://rebrickable.com/mocs/MOC-30630/Didumos/42099-b-model-rocky/.
A rock crawler buggy with a body tilting angle that averages the angles made by the front and rear axles. See: https://www.eurobricks.com/forum/index.php?/forums/topic/173733-moc-42099-b-model-rocky/