When comparing Ren'Py vs Flax Engine, the Slant community recommends Ren'Py for most people. In the question“What are the best game engines for point & click adventure games?” Ren'Py is ranked 7th while Flax Engine is ranked 54th. The most important reason people chose Ren'Py is:
Available on Windows, Linux, OSX, iOS and Android.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Cross-platform
Available on Windows, Linux, OSX, iOS and Android.
Pro Active and friendly community
Pro Reasonably good at creating puzzle and point-and-click games
Pro Free
Can be used for free until you hit a rather high revenue cap, at which point you have to pay royalties.
Pro Powerful C# scripting
C# scripting is really well made, comparable to Unity, but without any of the legacy cruft.
Pro Multiplatform
Supports most platforms, including Windows, Linux, Android, Nintendo Switch, ...
Pro Modern rendering backend
Has a very modern, performant and beautiful rendering backend.
Pro C++ support
The entire core is written in C++ and it supports writing game code in C++. The interoperability between C# and C++ is also nothing to scoff at.
Pro Supports multiple IDEs
Works with any text editor and comes with proper support for Visual Studio, VSCode and Jetbrains Rider.
Pro Excellent documentation
The documentation is well written, up to date and accepts improvements from the community.
Pro Great and extensible editor
The editor is both powerful and simple. My favourite part is how easy it is to extend the editor with custom magic.
Pro Source code available
The entire source of the engine is available on Github, though not under an open source license.
Cons
Con Not for every genre
While technically capable of creating 2D games in any genre, Ren'Py excels in creating visual novels and has a reasonable feature set for creating puzzle and point-and-click games. Other genres are best tackled by other engines.
Con Outdated Documentation and official built-in tutorials
Unfortunately, you will have to hunt relevant info on how Ren'py script works. The Ren'Py dev has the working tutorials on his Patreon, other than that you might as well just code in Python.
Con Requires knowledge of Python to use
Con New software
As is standard with new software, not all of the bugs have been ironed out yet.
Con Few plugins
Unlike more mature engines, there isn't a vibrant ecosystem of plugins yet.
Con Not open source
While the source code is available, it's not quite open source
Con Not latest C# version
It uses Mono and is still on some variant of C# 7.
Con No OpenGL support
It only supports modern APIs, namely Vulkan and DirectX. This means that it won't run on very old machines.
