What a great writeup, and of some pretty creative uses of particle systems to boot. Thanks to both of you.

Is there a piece of your code where powerups are marked as collected or destroyed? In that chunk of code increment a score variable that you initialize to zero upon entering the game state. It all sort of depends on how your game is structured as to how you go about keeping track of things. an overl...

If you're going to go davisdude's route you might also notice that your slopes happen to already be in a useful form. In addition to being a "triangle" they also represent a 2d vector you could pretty trivially apply to your character.

If you're making a platformer, your take is pretty much correct. Check to see what kind of tile is below you, which -- while it is a trickier question than it seems -- is something you can definitely muddle your way through and learn a lot from. There's a rad article about slopes and curves in refer...

you're also not removing it from the toRemove list.

You should probably make sure the object you're trying to draw actually has a body before you ask it anything about its body. It'll get self conscious and throw an error like that one. Once you destroy the fixture the body becomes unavailable, and you're trying to draw it by using its body. No biggi...

If you want someone to be in it for any kind of long haul you need to have trust and respect. Those are difficult to engender, but there are things you can do to help them along. You can pay them, you can exchange work for them, or you can do something notable enough that they approach you in the fi...

Incredible job! I could never do anything like that :P I spent about 10 minutes just moving about and being fascinated. The code wasn't all to confusing either(granted I only looked at main.lua). I assume the Vector thing was a library or something? Or did you make it? Sure you could! I actually do...

Making some 3d projections for a city. It's still limited, but getting better.

it is significantly slower than ipairs, but not worth worrying about.

also, if you want to get at one of those objects, you'd do or to make it something you can access programmatically