I think using a teleportation mechanic like The Lab, Budget Cuts, Talos Principle etc. would be the way to go - just limit the distance you can travel with a 'jump' teleport as some constant * your height. It doesn't need an in-world explanation, I think - teleportation is just the bog-standard VR movement mechanic 🙂
I only just got a VR setup and even so a couple days ago I was like "I'm sure there was this time-limited VR puzzle game where you got smaller and smaller and had to mix up chemicals, where is it in my steam library?".. hah! Your game must be pretty good if I thought I'd already played it in VR!