Initially irritating but new weapons add enjoyment. Filled with amusing references to Star Trek and the Wasteland below
However, once you get over this things improve somewhat. The levels are filled with homages to Science Fiction from the 50's to the present and the final stage is a definite homage to Star Trek. The new weapons are also a lot of fun, they are big, shiny and fire big blasts of plasma-type energy. References to the Wasteland do abound which helps you remember why you're playing this in the first place. The visuals are bright and colorful in contrast to the rest of the dlc and it is somewhat refreshing, but it often feels like a separate game altogether. At one point you come across a conveyor belt filled with weapons and items from the wasteland and there are even some hidden weapons worth grabbing. The aliens are odd little critters and you never learn much about them other than that they are trying to replicate certain things from Earth such as the buttercup robotic horse, of which you can find a toy version to bring back if you look hard enough.
It's also worthy of note that if you have a high science skill (75 or above) you can get a lot more from this dlc including special weapons and more interactivity with the alien technology. Again, this would have been nice to know in advance as several of the areas are blocked off if you plan a return trip. Perhaps the best thing in Mothership Zeta is stealing the cool gear from the samurai and cowboy characters you find beamed up alongside you and it might be worth playing just for this opportunity.