First, explore until you find the shop/rest area. The blond haired woman behind the first counter will sell you a room for 1000G, but you only have 900. You can make up the difference by finding 5 herbs in the dungeon (one is near the beginning, and the other four are in the area with the hands). Note that there is one hand placed in such a way that you can't get past it - there's no herbs past that one.
Once you gather all 5, go to the girl in the black dress (right side door in the rest area) and sell them. Then talk to the blond woman and buy a room. Go upstairs in the room and to the left - this is now a teleport hub, once you find other waypoints. Now you can go back into the dungeon, and the hand that was blocking your way before is gone. When you get to the large dirt room, there is a teleport spot at the top, and a room full of water at the bottom
(make sure to enter it and see the scene). If you talk to the shop girl, she'll suggest obtaining a rubber slime. To find it, return to the dirt room and continue northeast, winding your way through the dungeon. There's another teleport spot in the zig-zag room with slime pools, and the rubber slime is at the other exit (it only appears if you saw the water room scene and talked to the shop girl!). When you examine it, it will wrap around the character, and you have to hurry back to the rest area. You can take the teleporter (easy, ~2 hearts) or walk around the long way using a new path that opened up (hard, ~4.5 hearts). Either way, as soon as you step into the rest area, you turn the rubber slime into the shop girl and the demo ends.
