Makecode Arcade

• Make 8-bit style games in JavaScript or Block Editors with MakeCode Arcade
• Plus a set of tutorials that take you through creating a basic platformer in MakeCode Arcade then adding various game mechanics to it.

Bitsy

Bitsy is a tiny editor for making little games and worlds (like this one set in the British Library).

PixiJS

Tutorials on making JavaScript games in PixiJS (used by companies like Disney, YouTube, BBC)

The Code is the Game!

• Untrusted: a JavaScript game you play by editing the JavaScript for the game!
• Coding Game: a site where each game exists but you have to code your moves to play

Unity

You can get a free personal license for this games development tool used by professional games developers. There are lots of tutorials available to help you get started

• Raspberry Pi: Unity learning paths: text and screenshots guide you through making a 3D game
• Unity Tutorial for Complete Beginners: A video tutorial that gets you started by building a "Flappy Bird"-style game.
• Unity Pathways: Unity's own learning materials, text plus videos.