There is a lot to say about what to do and what not to do in VR; a simple google search will lead you to a lot of good advice. I highly recommend doing a bunch of research on your own, but more important is doing a ton of in-person experimentation. Most assumptions don't survive your first prototypes in VR.

Here are some things I think aren't considered often enough when it comes to VR development:



IMMERSION IS EVERYTHING

Immersion is the killer feature of VR. Whisking someone away is amazing. Protect this at all costs.





FIDELITY CONTRACT

This is the idea (originally described by Dr. Kimberly Voll) that you set up a contract with your user whenever you design something. You and the user agree on certain terms that you set forth:

Yes, barrels painted red always explode. Yes, there is physics to play with. Yes, you can explore freely in this area.


This is the framework that the player holds in their head while immersing themselves into a product. If you violate any of these expectations - if you change the fidelity of the experience unexpectedly - you break the contract, and your players get frustrated or stop caring about the experience.

Level 2 contains red barrels that don't explode inexplicably. You shoot at a beer bottle and it doesn't move. Invisible fences unexpectedly halt your exploration.


Find your level of fidelity, identify it, and adhere to it at all costs.

Paint those barrels green. Replace the beer-bottle with an anvil. Place a cliff-face instead of an invisible fence.


Here are some common violations I see in VR:



VR is different here than flat-games. It used to be fine to put a piano into an FPS, because players lacked the requisite fidelity to play - you usually only have a gun, or at best a clumsy "E to Use" button. Nobody expected to be able to reach out and touch the instrument. If you model hands, it makes sense that you'd be able to play a tune on the piano. It's the expected consequence of having hands near a piano. It's the fidelity contract.

"The obvious solution is to not include a piano in the first place. Or if you must, close the lid over the keys. And bolt the lid down." - Valve


The fidelity contract is so key that a single violation - even if that's just a feature not working 2% of the time, or an IK rig not behaving in extreme circumstances - is enough to ruin the immersion for the whole experience. You need to conform to the fidelity contract as much as you should be hitting framerate.



NON-NATURAL MOTION

Getting motion sick is unpleasant, and it gives the VR industry as a whole a bad rap. The more motion-sickness-inducing games launch, the longer it'll take for the industry to really take off.

Some people get their "VR legs." For others it gets worse the more they use VR. If your game induces motion sickness, you are taking a very big gamble that some big chunk of your audience will get sick. "It's fine for me and my team" isn't good enough - do some playtests with VR virgins and see what your response is like. Consider putting a motion-sensitive person on your team to be the canary in your coal mine.

I have not yet seen a sickness-inducing-game succeed commercially. Some high-profile AAA bad-examples have even dramatically flopped in this space. Tread carefully!

Here are some methods of locomotion roughly ordered from best to worst:



You can do some clever physical tricks (requiring the player to "jog on the spot" to move for example) that have had some success at reducing motion sickness, but nothing so far seems to completely eliminate it.

Yes, I realize that non-natural motion may be required for your design. If so, that's unfortunate! Just know that there are design ideas out there that don't require non-natural motion. Yep, they're harder to think of and execute on - decades of availability bias have been training us to design open spaces and fast moving vehicles. You might have to dig deep to find something that resonates that doesn't require this stuff! Frankly, this design challenge is why I'm so excited about working in VR. Do something new! Challenge yourself!

But if you must stick to non-natural-motion - at least try to mitigate it, and prepare your studio for the potential of decreased sales and/or bad press.



ACCESSIBILITY

A lot of people dismiss accessibility out-of-hand because they pereceive the less-able market to be too small to be worth considering. Other than just being a shitty attitude, it also makes your game much less resiliant to non-human-change: batteries die. Players don't always have tracking near the ground. Some play seated. By making your game nicely accessible, your game becomes quite resiliant, and something to be proud of to boot.





GENERAL STUFF





SASS





This is one of a handful of VR advice pages I've written. Check out the index for more.