Here's my belated attempt to figure out how fast the sun is setting. I'm assuming our sun over our earth─a 24-hour day. The image below is my crude effort (I'm pretty gimpy in GIMP) to identify the outline of the sun in the last few frames before it gets involved in the tree. It's hard to judge what of the white circle is supposed to be actual sun and what's supposed to be glare, but from the very latest frames I'd say my circles here are a bit scanty, and that the sun is actually moving about its own diameter every two frames.
The earth rotates about a degree every four minutes. The sun, like the moon, spans about a half-degree of arc in the sky, which means it takes about two minutes to move its own diameter. So, if my circles are as undersized as I think and I haven't totally mustarded my calculation, the sunset frames are only about one minute apart. Megball are moving rather slowly, but not impossibly so; it's only been about seven minutes since they walked into the scene. And in four more newpix the sun's upper limb should barely be showing; in five np the sun should be gone.
Darn, I was hoping to get this posted before mscha coma'd. I could use a second opinion; I don't trust my figures when I'm this tired. (I'm too tired for pagal decrees; I nearly forgot to attach the image.)
Good coma, Waiters! "The sun'll come out, tomorxip! Bet yer bottom dollar that tomorxip, there'll be sun!" Good night, Mrs. MobTeeseboose, wherever you are!
Edit to link to xkcd.mscha.org; forum upload shrank my PNG.