Hi, yeah you are right, it is impossible to reach this switch with the sword.
You have to get the firestaff first (which is located in the same summer/sand dungeon) and use the firestaff (with right mouse button) to shoot a fireball to activate the switch.
Better solution would have been to use a different hurdle maybe a hole so that the player understands better that this switch can`t be reached on the normal way.
In the end we had not enough time to polish a lot of elements of the game. And this is sadly one of those areas.
We would love if you give it another try after this "tip"
Thanks for your feedback!