playdate.timer.performAfterDelay() not running callback

Hey y'all. New Lua dev and PlayDate owner here.

I'm following along with SquidGodDev's video, and the enemy spawner uses performAfterDelay(), and I've checked it a million times, but the callback never seems to run, no matter what the delay is set to.

You can check out the file in particular here, which I've copied and pasted locally with no success.

Figured it out! I forgot to add playdate.timer.updateTimers() to the update() function in main.lua.