That D20 can catch up fast if you need to double back for a missed collectible... Nice. :)
What was the point of jumping though? Seemed like you could only jump as the D6, and if there was a prompt showing when you unlock sprinting, I must have missed it. I just accidentally discovered I could use it.
But I enjoyed it! Surprisingly tense.
One more note, since this is in Unity: You can use Cursor.lockState = CursorLockMode.Locked to keep the cursor in the center of the screen and hide it. You can set that back to CursorLockMode.None if you need to re-enable it for menus or something.