If you don't like point and click adventures, you won't like this. If this is among your first point and click adventures, you won't understand or appreciate this game. Play a few others first. At the very least, play the Monkey Island series first.
These two games contain two types of humor: absurd, potty humor and jokes that poke fun at point and click game design and the thought process of players. Some of my favorite moments in the game happen when Ben and Dan bicker about picking up random objects or trying to combine two very different inventory items. Ben and Dan frequently break character to talk about the merits and downfalls of the genre. They are aware that they are living in an adventure game world. I view these games as commentary on point and clicks first and a ridiculous tale about time travel, aliens, and Hitler second. The art style feels intentional rather than amateur. One of my favorite aspects of adventure games is the wide variety of art styles, so the graphics here don't bother me at all.
That said, I think that the first game (Ben There, Dan That) is slightly stronger because its jokes don't stoop to the same level of disgustingness as its sequel. Some of the sequel's jokes nearly cross the line and seem to exist for the shock value. I appreciate the humor more when it's better integrated with the point and click meta commentary. There are also a few puzzles which, while funny, aren't very intuitive. Especially in the sequel, you'll be asking yourself "What's my overall goal again...?"
I'd rate both games 4/5. I enjoyed them because I enjoy point and clicks. And when I play other adventure games in the future, I have no doubt that Ben and Dan will be in my mind cracking jokes about the silly inventory items I try to combine out of desperation.