It’s really surprising how little I remembered from the second half of the game. After storming the prison to free the general with the rebels, it all seemed unknown… until the construction site, which I actually did remember again.
Concerning your amazemenet about the change in style at this point, I think the whole game is supposed to be about the modern-times, industrial world (represented by Funfrock and his minions) taking over a serene world which used to be in a magical, peaceful balance. After all, even in previous sections, you could see Funfrock’s army using tanks and other mechanical machinery. In that sense, I find it fully appropriate for this last secton to be about complete desctruction of the natural environment.