Not having read the fic (I'm not familiar with Strangers with Candy, sorry) I'm a bit in the dark, but I'll try to critique anyway.

The face on the standing man is very nicely done. It's hardest to get the proportions right when the face is head-on. Nice hair too. I think the fingers on his right hand need a slight adjustment: hooking my fingers over my own arm to check, the fingers all are positioned slightly differently -- in particular, only one knuckle of the pinky is visible when two knuckles of the other three fingers are showing. In fact, the positioning of that arm seems unnatural.

The face on the seated man is off -- his left eye is too close to the bridge of his nose, and is shaped differently from his right eye.

The background is lovely and appropriate. You obviously spent a lot of attention on the tux too, with good effect.

I'd like to give you a higher technique score based on the face/head of the standing man, but I'm taking off for the things I've noted above -- because I know that you have been drawing regularly for years and I have seen what you're capable of, I'm a little more strict with critiques for you. ^_^