It was a simple line-drawn graphic style. One of the puzzles involved raising and lowering water level in some locks to get a boat through them. I seem to recall another level where you lifted a ramp, and installed some puzzle pieces underneath it.

I think one of the levels had a crashed alien spaceship in it. Some levels included color-coded pipes, and a vacuum tube message system. I think there was another level with a mouse that ran around inside a set of tubes you could re-arrange.

It tended to re-use the same assets such as cabinets and shelves from room to room. Almost all of the environments were drawn in single-point perspective, with the vanishing point in the center of the screen.

There was another puzzle that involved a knight's tour, or at least getting a knight to a specific place.

The author of the game used to add new levels from time to time. It's now been many years since I last played it, and I'm curious if he's added anything else to it.

There was a guestbook at the end of it, that showed a quill and ink on top of a desk.

I can picture the levels almost exactly in my head, but I can't for the life of me remember the name.