I could see this get ugly, Russia for the most part have ignored civilian population (that tank running over the bloke's car was disturbing though), but if the Ukraine army gets desperate enough, they're going to start to hide in apartment complexes, house, etc., just like how the Polish rebels did in the Warsaw Uprising during WWII. This will make Russia start turning and conduct bombing of these complexes regardless of if citizens are in there or not. Russia is supposedly sending in another troop division and have gotten two major airports around Kyiv. You're right that this can devolve into Afghanistan where the Ukrainian troops conduct "hit-and-run" tactics like the Taliban. That's much harder to fight because you got these huge convoys against quite effective small teams. Plus, it seems that a couple of countries including the United States gave Ukraine weaponry like anti-tank and anti-air rocket launchers.