Those are vintage screenshots.
It appears to look like this nowadays: https://play.freeciv.org/webclient/?action=new
It appears to look like this nowadays: https://play.freeciv.org/webclient/?action=new
Th web based game works great (and IMO the graphics are certainly polished to at least civ3 standards).
Some people appreciate retro looks, but everything from the sprite resolution to the colour palette feels like a nineties aesthetic.
There's also some layout logic at work. If you look at the way the units are aligned in the tileset you may notice that defensive units point right and offensive units point left.