There don't have to be any principal differences. If you find some, feel free to write to the bug report section.
The only suggestion I can give is to try to make materials simpler because VR is quite hungry for GPU resources.

Вы можете скачать обновленную версию здесь.

Список исправлений:
1) SSAO не приводит к падению движка на устройствах без поддержки DEPTH-текстур.
2) Автоматически уменьшенные Cubemap имеют корректные оси.
3) Нодовая анимация и set_nodemat.. работают корректно для мира.
4) Форсирование webgl 1 на всех устройствах с Qualcomm Adreno.
5) Настройка Physics AUTO работает корректно для линкованных объектов.
6) Исправлен редкий баг с дрожанием EYE-камеры.
7) Исправлены "засыпающие" объекты на демо HTC Vive.

You can download updated Blend4Web SDKs here.

The list of bug fixes includes:
1) SSAO doesn't crash the engine on devices without DEPTH-textures support.
2) Automatically resized cubemaps now have correct axes.
3) Node animation and set_nodemat.. methods work correctly for World.
4) Force webgl 1 on all Qualcomm Adreno devices.
5) Physics AUTO setting now works for linked objects as well.
6) Fixed rare shimmering bug for EYE-cameras.
7) Fixed sleeping physics objects on the HTC Vive demo.

Answered here.

Hi!

You have set preservedDrawingBuffer for 2D canvases. WebGL is drawn on 3D canvas.
What you have to do is just put the line to the exports.context obect in src/config.js file.

As for now, it is only possible to mix all the bones in two animations which is not suitable for you case.
I can recommend to use shape keys for eyes. They are applied with the following API

It the near future we will implement the full set of Blender skeletal animation features including animation of only a part of bones.

Представляем вашему вниманию новую статью по работе с Менеджером Проектов для начинающих:
Ссылка на статью

Check the new article on the Project Manager basics by Andrey Prakhov.
Link to Article

I see your point.

Being slightly slower, procedural modifiers can bring lots of benefits anyway. We have plans to support such staff along with all Blender objects/bones constraints. This will enable to create really flexible systems.

In any case, the main benefit of Blend4Web compared to three.js is that all the work on models/animation can be performed and checked in the engine without involving programmers. This is a great timesaver in most projects. Also, don't forget about technical support. We always help in solving different tasks arising during the development.

Hi!
What kind of value do you want to change? E.g. the number of Subdivs? This is not possible currently, as Blend4Web applies most modifiers during export and some during initialization.

Or maybe I misunderstood the question and the target is material properties? Then you might be interested in these functions:
set_nodemat_rgb
set_nodemat_value