I spend an enjoyable time on that one! You have a good gameplay mechanic with a lot of potential here, clearly something you can built on (forgive me for any mispellings, english isn't my first language). It's a puzzle game so i think it's ok to make the player backtrack (since searching is basically a big part of that type of game) as long as you include visual clues to help him/her. Something like your staircase's ruins that suggest a brand new staircase in the past is a good exemple of that. My only concern is that the main character lacks a "coyote jump". It's not a fault to have a rigid character in a puzzle game but if you ask the player to go through short timing platforming phases then working on your main character's response to the player's command is i think a neccessity. Apart from that, i think all of you did a wonderful job and should at least consider building more on this short demo. Congratz to all!