It's not nearly that easy. It would be good to know what the minimum size is. If all you want to do is put a cube on the screen how large is the JavaScript blo

It's not nearly that easy. It would be good to know what the minimum size is. If all you want to do is put a cube on the screen how large is the JavaScript blob you have to download? Then, most games have tens or hundreds of megs of data. Does Unreal do anything to help this? An ideal HTML5/WebGL game engine would have many of the features of flash letting the game start with a minimal amount of data and downloading the rest in the background and/or on demand. I know of no WebGL game engine that handles that in any graceful and developer friendly way though I'm sure it will come at some point. On top of that you need to deal with where the user is coming from. Are they on a phone or tablet with only touch controls? A slow desktop? A fast desktop? Do you handle both mouse and touchpad? I've seen almost no games handle these issues. Almost all assume you're on a desktop with a mouse which might be true for gamers but is not true for most people browsing the web (mobile or desktop). For mobile you could check and tell them to download the app. Does Unreal deal with any of these issues in a dev and user friendly way? Until then though most Unreal->WebGL or Unity->WebGL apps will probably have relatively poor user experiences.