When comparing Allegro vs Adventure Game Studio, the Slant community recommends Allegro for most people. In the question“What are the best 2D game engines?” Allegro is ranked 19th while Adventure Game Studio is ranked 22nd. The most important reason people chose Allegro is:
The Allegro community has produced a lot of great tutorials and resources. Allegro [Wiki](https://wiki.allegro.cc/index.php?title=Main_Page), Mike Geig's Allegro [Tutorials](http://fixbyproximity.com/2d-game-development-course/), Rachel Morris' [Tutorials](https://www.youtube.com/watch?v=E4RqHtEAAds), CodingMadeEasy's [Tutorials](https://www.youtube.com/playlist?list=PL6B459AAE1642C8B4&feature=plcp).
Ranked in these QuestionsQuestion Ranking
Pro Supports desktop and mobile
Support for Windows, Mac OS X, Linux, iPhone, and Android
Pro Good engine architecture
Allegro is well designed, easy to use and has many useful features.
Pro Good documentation and lots of tutorials
Since it has been in development since mid-90s with hundreds of people contributing to both the engine and documentation, it has all of its bases covered when it comes to standard support.
Pro Per-platform library optimization
Allegro uses DirectX for Windows, and OpenGL for other targets.
Pro Freedom to implement your own game engine
You are not bound to the limits of existing game engines, and you can actually implement your own engine.
Pro Easy to learn tool
Good for newbie game creators. Can be used for prototyping: on several occasions was used to make a demo/experimental version before creating a final commercial product on different engine.
Pro Completely free and open source
AGS is licensed under Artistic License 2.0 and is completely free for use for creating both freeware and commercial games.
Pro Relatively well documented
Besides the manual there are multiple text and video tutorials and code samples written by community.
Pro Used for a number of high-profile commercial releases
Adventure Game Studio has been used to develop games such as "Resonance", "Blackwell" series, "Gemini Rue", "Primordia".
Pro Lots of assets available
An extensive library of game templates and script modules accumulated over years. You can construct a simple game in hours (if you know what you are doing).
Pro Friendly community
An old, big and active community which would support newcomers not only in learning basics of the engine, but can help with every aspect of game making (including art, voice acting, moral support, etc).
Con Learning curve for hobbyist developers
Hobbyist developers coding alone may experience a learning curve with Allegro of about 200 hours (if you are rusty on C++). To learn quickly, see Mike Geig's tutorials at Fix By Proximity. This learning curve may be fine if you are considering going professional, but are still unsure.
For hobbyist developers not planning on going professional, you may want to look into a complete 2D game engine, rather than a coding library. For example, there are "non-coding" engines that provide support for coded plugins or scripting. But, if you are a dedicated hobbyist planning to use Allegro as your coding library of choice, you can still develop great games as a hobbyist.
Con Isn't great for C++
If you are a fan of object oriented programming, and want to use this library, then the chances are that you are going to be creating a lot of wrappers for functions in this library.
In short, if you're a C++ person, it could be recommended to check out SFML instead.
Con Development is slow
Further development of the engine is currently slow, done by only few people in their free time.
Con Assets cover almost exclusively adventure/quest genre
The features, script functions and game templates are very biased towards adventure/quest genre. The non-adventure games were made in AGS (2D shooters, platformers, turn-based strategies), but their development usually requires to write everything from scratch.
Con No visual editor for scripts
You have to actually write all scripts yourself.
Con AGS Script isn't as full-featured as other scripting languages
Its own scripting language has lower syntax capabilities compared to modern script languages.
Con Workflow is closely coupled with the editor
Workflow is very tied to the editor and custom file formats, which can cause problems for bigger, more professional projects (interfering with source control, parallel development, automated builds, etc)
Con Graphics renderer is a bit dated
Graphics renderer is not well optimized for high-resolution games and complex effects.
Con Uses dated tech
Engine is based on the old technologies, which impose number of limitations and may cause problems on latest systems (level of annoyance varies depending on your priorities).
Con Natively supports only 2D
2D only native support, 3D could be supported with plugins though.