There are lots of negative comments. So I may as well complete the list: - Fundamentally you have to code UI within JS. It's like doing document.write('<div></

There are lots of negative comments. So I may as well complete the list: - Fundamentally you have to code UI within JS. It's like doing document.write('<div></div>'); without .html file - Physic lib is totally useless on mobile. It's slower than pure JS - Flex grid doesn't work well when you make browser size larger and then smaller. You can see the UI not being refreshed.