Main reason I am not too convinced with HTML5, it's cos it seems to only be effective on new and powerful hardware and devices. I have no idea if this is going to change in the future or not, because quite honestly, isn't this a really bad setback? I have three computers, one with a crappy video card, Mobile AMD Sempron Processor 2800+ 1.60GHz and 1GB memory. Needless to say, HTML5 games struggle so badly. I have another computer with a 1GB video card, 2GB RAM and the same processor — It can take a bit more of a beating than the other computer, but overall it is still a laughable HTML5 experience. I have another one, this one is a Laptop with Intel(R) HD Graphics, 4GB of RAM, Intel Core i3 — 2.40GHz, 64-bit W7 Ultimate. This computer runs smooth most of the time, but it is considerably more powerful than the other two. Still, it doesn't run at full speed all the time though. When I was looking at the particle effects examples, it did not run at full speed either, most examples ran at 30FPS. My thoughts were, how am I supposed to run a full game that includes particles effects in HTML5 if only the particle effects alone are eating this many resources? The way I see it right now, to run a HTML5 game smoothly, you need a really powerful computer, that is preposterous, since most people cannot afford it and SHOULDN'T have to spend money on a new computer for the sake of HTML5 games.
Another issue is that with HTML5, as a developer AND user, you not only depend on yer native platform, but also on the browsers developers. This seems a little backwards to me, it is too much dependency.
Again, these issues need to be addressed ASAP by the HTML5 people if HTML5 really aims to be what it claims. Needless to say, native format 2D games all run fine on the three computers.
This is about HTML5 and it is not about C2, there's really nothing I can complain about this amazing tool. However, there's plenty that needs to be done to HTML5 and I really hope they resolve them.
EDIT: Also forgot, although it is possible to play HTML5 games offline, it is a hassle and surely much harder than installing an EXE game on a computer. A casual user is more than capable to install an executable on their computer, but how many are capable of setting up the computer for offline HTML5 gaming?