I’ve written a few of my own in plain JavaScript and it’s been a lot of fun.

Dungeon Memalign: https://memalign.github.io/m/dungeon/index.html

Source: https://github.com/memalign/memalign.github.io/tree/master/m...

Writeup: https://memalign.github.io/p/dungeon-memalign.html

Counterfeit Monkey (demo): https://memalign.github.io/m/counterfeitmonkey/index.html

Source: https://github.com/memalign/memalign.github.io/tree/master/m...

Writeup: https://memalign.github.io/p/counterfeit-monkey.html