In fact this one is even more cross plataform than LOVE. Well about "old gaming", this can be however what we want. But don't have the power and flexibility of LOVE of course. Probably this is more an alternative to JQUERY gaming libraries like gameQuery (
http://gamequery.onaluf.org/). Also you can check this one
http://www.effectgames.com/effect/
I did a quick run on this. I think even to those who don't know JS can do some stuff recycling the existing code. I checked pacman clone source in the package and code was well commented. Also the engine seems ok and well done.
Experienced the Zelda clone in both desktop and in itouch browser. Has support for a crappy virtual keyboard, however they still need to do basic things like hide safari UI (that mess with play sometimes). Also I saw a Safari crash for first time (in a idevice). Had some slowdowns too (2nd Gen Touch). Their demos should be remade since for example zelda clone have too small letters to be read on small devices. In desktop all worked fine.
There still other some small annoyances to fix on the engine. For example in the demos I needed some time to discover that "press A to start" was not A key. The examples were "optimized" for idevices virtual controls and forgot the desktop keys. But they can easily detect device and have a way display the correct commands for each device if they wan't. This is almost cosmetic but would help in portability of the games.
However seems interesting. If they can add some day some drag and drop editor this can even be a nice way of do easily games for no coders. For experienced JS coders will be optimized tools however and probably advanced JS coders will they prefer do their own from scratch.
bartoleo, one small tip, don't fall too much in the mistake of call it HTML5 game libraries (I know is even that is wrote on their site and they wrong) but that follow the stupid apple/media hype cliche. In fact are normal JS game libraries encapsulated in HTML5. The HTML5 code (well markup) here "per si" couldn't do nothing useful. Guess what? I changed the Pacman html5 to XHTML strict 1.0 and all was still working fine so I don't know really what "small" subset of html5 (as told) they are using. Unfortunly till someone gets a name for the mixed set of technologies used in Aple's HTML5 (html5+css 3.0+JS+other small web techs) that's the name that we will erroneous will see. At least In old times of JS discovery we had DHTML designation that made his work.