Thats strange, personally i find beginning and midgame interesting and endgame boring :) I ramp up alien evolution, expansion speed and increase size of alien attack groups, start a new map and try to survive, build base while being often attacked by aliens. That challenge is interesting. In the ...

TL;DR
Different track look on paved ground and train assembly plant.

What ?
When train rails are placed on soil, they have gravel/stones underneath for extra stability, but what if they had different look when they are placed on concrete, paved tiles - a cleaner, modern look? Maybe something like ...

recent design trend seems to be a bit too cartoonish (just an honest opinion)