Orb Chaser

You can either hunt or be hunted. This is a prototype/test of semi-random
automated movement. The way the enemy movement works is quite simple.
The little lines illustrate the behavior: the yellow ones correspond
to acceleration (or force), the blue ones to the resulting velocity.
Once an enemy's speed hits a fixed maximum value, it gets a new
acceleration pointing in a random direction (biased towards the player).

Hit [CMD+`] to go fullscreen on Mac and F11 on Windows.
If the canvas is too big/small you can zoom your browser window.

Hit the "Source" button to edit and run your own version of the code.
Any changes will be reset upon page refresh.

Source