Yea, i see the same in my games even on desktop.
It is linked to spikes in dt ( usually jumping from 0.0167 to 0.0333)
Has nothing to do with your code or capability of hardware
I believe it is referred to as "jank" in the business
and cannot be solved by using factoring for dt i.e framerate independence.
(as can be attested to the fact you are using sine behaviour in ur capx)
Ive seen some posters and websites link it to "garbage collection"
There is a test website that says that Chrome has VSync issues because of a 96MB GPU memory limit and various other > here http://www.vsynctester.com/chromeisbroken.html and other stuff possible totally unrelated to C2 development that you probably shouldn't read for your own peace of mind.....but I know nothing about these things
certainly this test http://www.vsynctester.com/gputest.html runs janky in Chrome even on my desktop and super duper janky on my phone usually ending in the aw snap crash ....but runs silky smooth with edge browser on surface pro tab and desktop....
they say that not using hardware acceleration i.e. disabling web gl will solve the issue in chrome but then I suppose you loose performance in other ways.
disabling web gl on your capx resulted in smooth scrolling in chrome but will prob result in an overall FPS hit on mobile for bigger games ..
What worries me is that Looking through the chromium devs emails (linked through from above)
it is clear that
1. They are very disorganised and work very slowly
2. There are tons of open issues related to vsync , jank, framerate stuttering
3. They dont really know how to solve them due to complex relationships between browser, os and hardware.
4. These bugs are considered very low priority so dont get much attention
I'm not sure I have seen the Scirra devs comment directly on it.
any chance you could comment