Okay so great work with completing your first game, alot of elements are actually pretty cool for a first game and deserve a mention. First off though I just want to mention a few things that can improve the game... the FOV is a bit weird and feels way to zoomed in. Go to the main camera and change the FOV or the sizing. The second would be the explanation try to add more hints about the objective of the game. Throughout the game I would randomly run into objects just to test if they were the key.
Great work on the WebGL export, updating ui elements and music. Most first games don't have these so good work.
There are still 10 days remaining, keep going with the project work on polish and improving the game feel.
Good luck!