Basic fuel mechanics

Besides energy (that is, health), you now have an amount of fuel. (Both are visible at the bottom of the screen.)

Warping between areas now costs fuel.

You start with 50 fuel out of 100 maximum, and warping costs 10. If you have less than 10 fuel, it slowly recharges -- so you can't get stuck in an area with no asteroids.

There are now "pickups" which can randomly pop out of asteroids when they are shot open. For now there are 2 types of pickup: energy and fuel.

Would be easy enough to add a "money" pickup which randomly pops out of ships when they explode... a bit hacky, but would be a way to quickly get towards adding basic "ship upgrade" mechanics into the game.