I came up with a game concept that made the most out of the 3dof headtracking VR limitations of the GearVR and was feasible within our small scope; The player had to solve optical illusions (that were on the paintings on the wall ) by using its head movements before the time ran out! Over time floor tiles fell, which indicated how much time the player still had.
I came up with the concept, researched what shapes for the puzzles worked and balanced the difficulty of the challenge by tweaking how much headmovement was required for each shape and how much time the player should get.
I also created the haunted and eerie soundtrack that puts the player on edge which also indicated when time is running out. I made sure this soundtrack provided enough atmosphere without it distracting the player.