"As it stands really C2 doesn't even really support HTML5 since they aren't implementing it themselves, just using others' implementations like Chrome and Firefox over which Scirra has no control, and in the case of changes (e.g. recent Chrome change to drop XP support) users may in some cases be out of luck. The fact that the Chrome team, which makes decisions best for browsers and not necessarily best for gaming, can affect how my game plays on a 'standalone' desktop application is not what I expected based on the C2 product description."
Just to correct it: C2 does HTML5 at the end, the problem is mostly do browsers actually respect HTML5
Same goes for crosswalk and node webkit, scirra does the HTML5 themselves, the problems are the interpreters, and that is a pretty big issue IMO.
Also the chrome issue wasn't best for browsers, not only in gaming, but also in some HTML5 standard like video reading it is a problem.
But I agree that sometimes I find the product description a little weird, and would prefer also a more reliable way to read that HTML5 across platforms.