When comparing Gosu vs AppGameKit 2.0, the Slant community recommends AppGameKit 2.0 for most people. In the question“What are the best 2D game engines?” AppGameKit 2.0 is ranked 25th while Gosu is ranked 50th. The most important reason people chose AppGameKit 2.0 is:
The AppGameKit Basic can now export to HTML5.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Lightweight
Gosu is not a game development framework, only a media library that happens to be suited to game development. (Kind of like SDL in the C world.) That means the interface is relatively small.
Pro Mature API, actively maintained and developed
Gosu has been under development since 2001. It is mature and has several toolkits built on top of it to provide additional functionality.

Pro Cross-platform, even mobile, using Ruby
Pro HTML5 support
The AppGameKit Basic can now export to HTML5.
Pro Cross platform
Supports developing games for Android, iOS, PC, Mac, Linux and now HTML5.
Pro You only need to to pay for the license only
There is no charge for upgrades, or for extra platforms (the HTML5 version just appeared in the latest version), there are no subscription fees or other usage charges. If you publish onto either Apple or Google's stores you will have to pay their costs, of course, but the makers of AGK do not take a cut of this themselves.
Pro Plugin support for Windows
Plug-ins can now be added to the Windows platform. Create your own Tier BASIC commands and call them using the AppGameKit Basic script language style.
Pro Instant testing on multiple devices at once
AppGameKit supports instant testing on all connected devices. With the push of a button you can run your game on any device connected to the development machine.
Pro Excellent documentation
Every function is fully documented with examples and exercises. The Tutorial PDF is a full Introduction to 3D game programming with integrated references to every functionality and its most important usecases. The documentation is regulary updated.
Pro Easy basic programming
Program in tier 1 BASIC programming for every 3D game need.
Pro Raspberry Pi free version available
A Raspberry Pi version is available and free. Users just need to register with the developer and then they can download.
Pro Very fast compilation
It is a compilation based language, but the compilation is very fast. A project of about 1800 lines of code, for example, can compile almost instantly. (That's because it does not compile, it's an interpreter)
Pro Support
Informed, timely and intelligent feedback from the AGK forum.
Pro Fast development
There are plenty of functions which facilitate development and deployment. For example, the AGK player immediately plays the updated bytecode on Android devices then the online site helps with building an APK file for Google Play Store in minutes.
Pro Uses a powerful scripting language built for game development
Software produced with the App Game Kit is written in a language called AGK Script. This language has powerful inbuild commands including commands for 2D graphics, physics and networking. The commands make use of the platforms' native functions to improve performance. They are also designed to enhance code readability. The AGK Script commands have extensive online documentation.
Pro C++ and Basic, you have the choice.
It runs fast with BASIC but if you want more you can use C++, it's also easy to use.
Pro Can be used for advanced games programming in C++
Libraries which provide the same functionality are available for the five platforms, so you can code in C++
Pro Comes with an Integrated Development Environment (IDE)
AGK comes with an Integrated Development Environment (IDE) based on the Code::Blocks IDE for writing AGK scripts. A key feature of the IDE is its ability to broadcast compiled programs to other devices for testing.
Pro Performance
Cons
Con Deploying Ruby apps is a mess
Games built with the Ruby to .exe "compiler" do nothing more than extract your source code and Ruby.exe to %TEMP%, then run it. The code is not really compiled at all. The process for wrapping games as Mac apps is a bit nicer, but you'll need a paid Apple Developer subscription to code sign the app, or users will see a warning/error when running your game.
The only way to really compile Ruby is to use RubyMotion, which does not work on Windows and requires a paid subscription on top of the Apple Developer one.
(This Con is not specific to Gosu. Deploying Ruby code has never been fun.)
Con Restrictive virtual buttons
"AppGameKit" does not grant editing the very basic parameters of virtual buttons such as font and text size. The only method some people suggest is to use an image for every single "button".
Con Terrible scripting language
MS Basic from the 70's has more features. Procedural, no OO, inheritance, basic user defined types with overloading. Nothing. It even has GOSUB.
Con BASIC language
Even though it supports C++, it's mostly C++ mapped to BASIC without OOP.
Con Can almost only do trivial games
The editor is rather limited, not fully polished, and 3D is missing some key functionalities (3D is work in progress).
Con No builtin game mechanics, events, inventory.
Con $80 even if your game doesn't fly
Con Editor code completion is pretty bad
Con Pros on Slant are written by AGK marketing guys
