Games

Twine

• Games
• Interactive Narrative
• Writing

Write interactive narrative fiction (the online version). Create your own adventure game!

Godot Engine

• Coding
• Games

Free, open source games development environment. One day, I'll get round to having a go with Godot.

GDevelop

• Game
• Games

Create 2D games without coding. 

Study Crafter

• Game
• Games
• Interactive Narrative

An amazing tool to create interactive games with a flow-coding interface, but equally could be used to make training materials. The primary use for this tool is to collect research data about what choices people made.

Free.