Flash vs HTML5 game development for web & mobile [closed]

Question

I am an experienced AS3 programmer, and I've done Flash apps and games on the browser and on mobile (via Adobe AIR, e.g., on Android).

I am about to start developing a game (basic 2D platformer with pixelart graphics. Think about Super Mario World) targeted to both web and mobile platforms. Thus I'm searching for easy deployment to these two kinds of platforms, having basically the same source code.

I'm divided between choosing ActionScript 3.0 (Flash) or HTML5/JavaScript for developing this game.

My main question is, for those who've experienced the same situation before:

What is the safest way to go?

In other words, are there serious disadvantages with one of these frameworks that disallows me to develop multiplatform 2D games?

Or am I just dreaming and practical multiplatform (web and mobile) game development is not so possible? (does someone know how Rovio did it with Angry Birds?)

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Here are some pros and cons that I already know:

Pros for AS3/Flash:

• The state-of-art for web games.

• I'm experienced with it.

• (Almost) concealed source code.

• On the web, it's browser-independent.

• Can run as a "native" app on iOS and Android through Adobe AIR. It's not the best performance experience ever, but I know that you can get playable performances with it.

Cons for AS3/ Flash:

• Performance on AIR for mobile is not optimal, so I might end up having to abandon a really cool but expensive feature (or even several features).

• People are saying HTML5/Javascript will substitute it.

Pros for HTML5/Javascript:

• It's possible to do Flash-quality games using, e.g., engines like ImpactJS or Akihabara.

• Seems to be more stable and well supported on mobile in the future.

• Deployment as native app is possible through PhoneGap, appMobi, etc.

Cons for HTML5/Javascript:

• I have some basic knowledge of this technology.

• Source code is wide open exposed.

• Performance/behaviour is browser-dependent.

• Lacks a solid framework or engine which is free of co$t$.

Answer 1

I've decided to forget about HTML5 for cross-platform game development, and specially for deployment to mobile.

The cons I've pointed out for Flash are much lighter than the cons for HTML5. Basically, for the pixelart kind of games, Flash on mobile performs really well, specially if using some nice engine like Flixel.

For example, the Flixel game Robo Run has great performance both on Android and Flash Player in a browser. I don't have an iOS example for the same game, but I believe it would perform as good as on Android.

Plus, Flash performance on mobile shouldn't be an increasing problem since the hardware on these devices just gets better and better.

After thinking about this HTML5 vs Flash issue for several months, I think there's no point adventuring in HTML5 cross-browser compatibility since Flash has proven to be a sort of Java for 2D games.