What are some alternatives?
When comparing RenPy and Stencyl, you can also consider the following products
GDevelop - GDevelop is an open-source game making software designed to be used by everyone.
Unity - The multiplatform game creation tools for everyone.
Unreal Engine - Unreal Engine 4 is a suite of integrated tools for game developers to design and build games, simulations, and visualizations.
BYOND - BYOND is the premier community for making and playing online multiplayer games.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
ct.js - ct.js is a 2D game editor (desktop app) based on web technologies.