In this video I add some enemies to the platformer, including a simple player-following AI and collision detection.

Previous part: https://www.patreon.com/posts/2018-03-02-demo-17330399

Source code for this part: http://okayideas.com/20180310/game.html 

If you appreciate these videos, or if you have suggestions to improve them, please let me know in the comments!