Here some of the walkthrough i found (not complete)
When you get to the first town, find the cloaked dude who "saved" you at the barricade, he's in the inn. Then go to north mansion top floor and talk to important looking person. After that go to weapon store, buy and equip a gun, go back to inn to talk to the cloaked person and curse at the npc that always blocks that one hallway. Then go to weapon store again and do the combat tutorial. Once all this is done, go to north mansion top floor and there's this fireplace that's actually a secret passage (near the stairs).
Ok, finally out of the first town. Now time to head to the second town. It's somewhere in the right side of this "main ruins" area. Once in second town, go to inn and talk to scientist dude. He tells you to get an item, go get it, come back and head to the laboratory that's on the right side of the town. Talk to him until he repeats himself and you get an ID card or something.
Next head north in the "main ruins" area. Just follow the big road and you'll find a boom barrier which you need to activate from the box part to open it. Go through the new area and you're in the third town. Go to the building in lower left area and talk to another important looking man to get an ID card or something. Note: Another thing you may need to do is talk to a little girl in red who's in another building to the right from this important npc. She asks a yes/no question or something.
Now that you're done with this place it's time to head to... no not the fourth town. Go back to the "main ruins" area and go to the lower left area which leads to another zombie filled area. Go through this small area and you'll find a lame abandoned factory. Go to the end of this place and do your thing (not sure if you get a gameover if you didn't talk to the little girl that was mentioned previously). Remember to grab shiny item.
When you're done with that place, head to the second town. If you haven't done so before, now would be a good time to spend all of your money. Maybe buy a new gun. Also check on the scientist dude, if my memory is correct he gives you a new ID card or stuff (I think there was a part where he teleports you to third town aroun here, if so just talk to important npc). This gets you to the fourth town which is behind a robot in the upper left area of the "main ruins" area. When you enter the town you'll regret not spending your moneys. Well you don't have to worry about money anyway because this is the part where the heroine remembers what she's always done to get money. You have to find 3 dudes, one is in the big building near the entrance, another one is alone in a house in the middle of the town, third one is in the northern part of the town in a pub. When you've talked to all three of them and they seem like they agree with you, go to the inn. You should now have 60k money.
Before you go and spend your newly earned money, go to the northern part of the town and find 2 npcs who sell you stuff for 10k each. Also go talk to the three dudes you were partying with. Then try to open the door of the red building in the middle of the town and grab the shiny item inside. These things should allow you to repair the orb near the inn (or talk to scientist dude in second town) which works as a teleport device between the towns. Also one of the 10k items you bought is used to open the boom barrier that's in the south side of the "main ruins" area. This leads to the fifth town.