I played this the other day, and i have some mixed feelings about it. The art was great and the puzzles were fun, but the plot was underwhelming. The main plot never seemed like the main plot, if you know what I mean. Every time we were given a objective, it feels like this will lead us to our final goal, and each time it is a let down. You are told to "do this" and when you do you are told "great, now do that." And when I got to the end of the game I got a sense of "what just happened?"
I was also disappointed in the female 'love interest.' When you fist see her she seems sort of interesting, and when she wakes up from a coma she also does something interesting. Then she is unconscious for almost the rest of the game and when she finally does wake up she looks like she is in a trance the entire time. Never before have I seen a character who was more interesting whilst they were unconscious.
All in all, I would favorably compare it to monkey island. They both have enjoyable humor and puzzles, but Deponia is somewhat lacking in plot and engaging love interest. If there is a sequel, I will buy it, if only because I was disappointed in Deponia's ending and would like some proper closure.