the expansion adds separate planets and multiple space-platforms. So it moves away from the monolith and towards multiple smaller factories. (In the end-game you probably and up with a massive monolith again, but until then you will have multiple medium-sized factories).
> ... classic tower defense and using the layout of the map to your advantage to extract resources and kill bad guys
Each new area add some unique defense-need, e.g. in space you have to shoot at incoming asteroids, and on the lava-planet, you have to build temporary mining-outposts, that get eaten by worms after a couple of minutes. (The other planes probably add something like that too, but I haven't played so far yet)
> there are many different levels each
the expansion adds separate planets and multiple space-platforms. So it moves away from the monolith and towards multiple smaller factories. (In the end-game you probably and up with a massive monolith again, but until then you will have multiple medium-sized factories).
> ... classic tower defense and using the layout of the map to your advantage to extract resources and kill bad guys
Each new area add some unique defense-need, e.g. in space you have to shoot at incoming asteroids, and on the lava-planet, you have to build temporary mining-outposts, that get eaten by worms after a couple of minutes. (The other planes probably add something like that too, but I haven't played so far yet)