purplemonkey This is looking really wonderful!
I peeped your dev log over at TIG and had a question: You mention not reusing art assets. Have you done any test exports with nw.js to see how it runs? Not doubting, just curious!
I answered a similar question on the Scirra forum back in April so I'll go ahead and quote my old self on this one. It's still working well like it did back in April, and we have tons of new assets, including a bunch of animations.
Layouts are about 10k and we're using multiple effects covering the whole screen at all times. In regards to animations, right now we've got 2 characters always on screen with about 35 animations each (and growing). Current estimated image memory is about 200-350mb per layout.
I have been trying to regularly optimize or at least not go overboard with different things but at the moment, this is all running in 1080p, 60fps on dedicated graphics and 40-50fps on my brothers Surface Pro 2, which has got an Intel HD4400 graphics card. I don't want to jinx anything but I'd say so far it seems possible.
If you'd like to see more about the game itself you can find info, screens and videos at http://yondergame.com/.
The videos do not show a whole 10k layout, since it's displayed in 1080p it's about 5-6 screen widths per layout.
We are most definitely not just throwing in 10k width images in the layouts. What we do is draw the whole layout using separate software and then output it split into smaller images. But we try to be aware as much as possible of where and what we can optimize. For example, the foreground in our game is mostly blurred and so the foreground images were saved in 50% size and then doubled in size ones placed in C2. So it is best to always be aware of the parts that really need to be sharp and the ones that aren't as important.