Yo-yo Shields!

I try very hard to come up with original things to set the game apart from other shoot-em-ups. The other day, I was thinking about defenses, and came up with a yo-yo.  Today, it's implemented! It springs back to the player via Hooke's Law, with a visible string tether. It will do damage to any enemy that comes in contact—but it's of course useless against bullets and virtually harmless to dense (grey) asteroids.

There's currently a limit of two, but you can do a lot of neat tricks with it. If you get enough momentum going, you can sling it all the way across the screen and back. I'm also aware of a very rare bug where it's possible to get it stuck in the top-left corner (and likely the other three corners, too, but I haven't seen that yet.) I'm going to address it but until then, the fact that it's possible doesn't mean it's easy. If you deal with that bug, feel proud; I can only assume that you're mastering the yo-yo.

Yo-yos don't have infinite durability, but it's pretty high.