Hi Raimonds,
the problem with Rectangles in published games is, that its rendering performance is quite low because the draw calls cannot be batched, which is a massive performance killer on mobile devices. Thus we do not recommend to use Rectangles in published games but only during development.With images you have the option to pack them into a sprite sheet, and get the best performance out of it.
Regarding the pause/resume request, this is already included and possible in Felgo, but it was not documented (yet) – which will be added in the next update, thanks for your hint!
Cheers, Chris