@BeTe
I'm bit biased here, as it is my mod and all, but you could try installing the Imperia Vetera mod for alpha 9. Just to see if that old "look" will suit your eyes. It's there in my signature, or here if you aren't logged in. You'd need the Alpha 9 exe in order to install it. I'm assuming you have Wine installed if you're playing Brood War on Linux.
https://releases.wildfiregames.com/0ad-r11339-alpha-win32.exe
Of course, there is no Multiplayer, and the features are pretty bare-bones. Nevertheless, the game did look different at one point in time.
My favorite civ to actually play as is Athens, though I love the Britains as well (such cute little war puppies). Mauryan trained war kittens (tigers) when?
I’ve had this happen, what’s causing this is that you have both Town and City phase specified as requirements for a unit/building, which causes this error message to appear (it only wants either Town or City as a requirement). Most likely one of the templates has a requirement for a phase, you need to remove it with something like “-phase_town” or “-phase_city” to fix this. @wowgetoffyourcellphone @Lopess.