As far as explanation, I had a lot I could have done. Even down in the description, I could have explained that you can spit on the guys, the max score, explained there was no end screen (oops).
The guys spawn more often with a higher score, and don’t spawn below a score of -10.
The fires spawn more often with a lower score, and don’t spawn above a score of 10.
This could’ve used balancing as it’s easy to get above 20, but very difficult to get below -15.
Oh, and the green guys probably make shuffling sounds and say “oh, hi there!” when they spawn and when passing one another “excuse me, sir”.
And when they’re mad they just grumble about “kids these days” - and maybe sometimes “ducks these days” - and some other inarticulate sounds.