Simple Shmup

This is a simple shmup for the Pico-8 fantasy console, written as an exercise to explore some basic features of the console.  Defend your sector from the loathsome Zargon menace!  Or maybe you're the Zargon, harassing innocent squishy green space-faring critters minding their own business...I dunno, whaddya want, I hacked this up in a few hours in a hotel room while watching Futurama.

Anyway, I wrote this to try out basic Pico-8 development.  I started with basic sprite movement using the arrow keys, limiting the range of movement to the screen.  I added a starfield background in the map using a handful of sprites.  Then I set up a data structure for the laser bolts, spawning them from the ship on button press and iterating over the structure to give them all their behavior.  When they run off the top of the screen, they are deleted from the data structure.  A simple square-wave bloop works well as a sound effect (the first Pico-8 sound effect I've created!).

Finally, I added the enemies and organized their data and behavior in a similar way.  I put in some basic collision detection (just testing if sprites overlap by a bit) and, if there is any, delete both items from their respective structures, show an explosion sprite, and play a little noise sound.  I used the same collision code to detect when an enemy touches the player, and show a Game Over message.  A basic score counter in the corner rounds out the package.

That's about it!  The whole thing took me a few hours to do, with a little bit of experience and a little bit of experimentation.