Having worked with embedded WebKit in games before, this looks interesting. However, even more than binary size or runtime memory usage, I hope Ultralight optimizes for responsiveness. In games we’re usually dealing with frame times on the order of 16 ms (or less for MR applications); any sluggishness in the UI immediately stands out. Often the UI masks more delayed gameplay feedback and for html/js to be viable as an embedded framework for games, it needs to be as fast as native implementations.