I remember seeing this for the first time on TV in a Swamp Thing marathon back when I was a kid around 1990 or 1991. I liked the live-action TV series too and remember sitting and drawing the character.
What a terrific film adaptation of a comic book hero! This one is a direct sequel to the first film (the Wes Craven-directed one). There's a very good balance of action, some horror elements, and noticeable a good amount of humor, especially with the two kids and Abby (played by the lovely Heather Locklear). The "knock-knock" part got me cracking. The soundtrack is synonymous as I remember it. Somewhere near the end as Swamp Thing steps in, you see his eyes gleaming through the shadow as he moves; very nice little detail there. The practical effects give it much believable visuals, and I really admire the costume design for Swamp Thing starting from this one and onto the TV series; a definite improvement over the first film. I've always liked Swamp Thing. He's a good man, defeating the bad guy and saving the girl. Now I feel like piping through the TV series if I can find it.