With the many different variations on the Cardboard headsets, do people favour a certain brand or type? During development I am evaluating the necessity of the single button/click usage at all, as sacrificing this for pure look-based controls means the game can be played hands-free for headsets that provide a head strap. This is appealing for prolonged immersion without arm strain and seems to be semi-common among currently Play Store games.

Secondly, with performance playing an important part in gaining valuable frames for VR, is there a minimum (recommended) spec people adhere to for preferred optimal experience?

I think the current cardboard best practise seems to be to avoid using the button and use gaze based controls instead. My game this time last year was really simple and didn't really use any controls other than tilting the head slightly forward to walk so it's possible to use no controls at all.

This time around I'm using a Bluetooth controller because I want arcade style controls seperate from the headset.

As for headsets if you've used the base handheld carboard for more than 10 mins you'll know most people interested in using it have spend the tiny amount a headset with a strap costs.

That is good to hear, because I'm well into development now and opted for a purely gaze-driven control system!

I thought I had read earlier that the GAJ wouldn't be accepting games using controllers, is that right? This might be a concern for the arcade controls you've mentioned.

I thankfully have obtained a non-Google Dodo Case (cardboard-like) headset and a more robust VR One plastic, strapped headset from a friend to develop with. While the comfort of the VR One is unquestionably a better experience, I've also observed that the field of view differs between them, and suppose I need to consider this into my game's viewport.

I can't see anything in the rules about controls. The previous cardboard contest allowed controllers and most of the successful projects used them so I presumed they would be allowed this time.

The viewport is pretty much always square and a lot more narrow than you need in mobile VR since we're all spoiled with widescreens for most of our work right now.

Interesting, I did find the reference to that, though not in the rules. It was in the Discord #general channel (3/3/17 by liu.archiact):

Hey @linojon we're just focusing on GearVR and Cardboard, and unfortunately we won't be using controllers as well

Definitely feel the restriction of the square viewport, but even between headsets the visible area does vary somewhat.

Bugger, I'll ask Liu on discord later on when I get five mins why it wasn't in the rules upfront. A bit busy at the moment (although I think a virtual me is idling on the channel because I've left my work machine turned on) but I'll get clarification.