You'll start facing three cupboards. The left and right cupboards are locked, and the middle one is held shut with screws. There are also two potted plants you can't really do anything with.

Above the left cupboard is a sink missing its tap head. Above the middle cupboard is a scale of some sort. That's all we can do here, so back away and turn right.

You're now facing the door, a sofa, and a nightstand. The door's locked, as usual. Look under the sofa cushions for a coin. The nightstand's drawer contains... a hole marked "100ml"? Weird. Also note the contraption on the nightstand, which is useless for now.

Turn right again to face a bed and two paintings. There's something beyond reach under the bed. You can zoom in on both paintings, and the left one reacts to having its corners teased, but you don't know the combination yet. There's also something hanging from a ceiling rafter, way out of reach.

Turn right one more time for the windows. Zoom in on the middle pane: there are stars in each corner. 1 in the upper left, 3 in the upper right, 5 and 6 lower left, 2 and 4 lower right. I think I know what that's for.

Now check out the chairs to the left. There's a Mr. Hippo ornament on the little ledge that we can play with, but it's not much use for the moment.

Spin the right chair. Click on it to turn it, and watch it turn back. Wind it up by clicking it nine or so times in a row, and it'll fall apart. Look at the post it was on and get the screwdriver from it.

Zoom out and turn left. Pick up the fallen chair seat.

Examine the chair seat in your inventory. Turn it over. 3035?

While you're here, zoom in on the left painting and enter the code from the window: upper left, lower right, upper right, lower right, lower left, lower left. The painting should come loose.

Take the tap head from the alcove (it's a little hard to see). Note the bolts holding the cover near the alcove's top.

Go back to the cupboards. Use the screwdriver to undo the screws on the middle cupboard, then open it to get the box... that wants a three-digit code you don't have yet.

What you're REALLY interested in are the symbols written on the wall inside the cupboard. Hmm... what could that refer to? One symbol changes at a time.

Go back to the Mr. Hippos in front of the chairs. Press the buttons in this order: right, middle, middle, left, middle. The hippos will open and close their mouths to match the symbols in the cupboard, and at the end you'll get some clay. Er... thanks?

Examine the clay and mess with it a little. You'll get a spade key.

The spade key opens the right cupboard, revealing a box that needs a combination of four symbols and a weird memo.

Maybe a little outside-the-box thinking will solve this one. Remember "3035" from the underside of the chair? Set the symbols to triangle, circle, triangle, pentagon (note the number of corners on each shape) and you'll get a steel cup for your trouble.

Put the steel cup in the device above the middle cupboard and it brings the scale to 0. Take it back.

Go put the tap head on the faucet above the left cupboard, then turn on a flow of water. Fill the steel cup with water. Also, use the memo on the water flow to wet it.

Put the steel cup in the device again. 1600 grams? The cup's capacity must be 1.6 liters. We need to get exactly 700 ml in the cup somehow.

Wait, look at the memo again. It looks like the head of the bed! Examine it and take the one rod that's missing in the memo's picture (second from the right).

Use the rod to retrieve the thing under the bed. It's a wrench head!

Combine the wrench head with the screwdriver, then use the result to undo the bolts in the alcove the picture was covering.

A gap? Hmm... I've got an idea. Put the chair seat in there, then click above it to climb up.

Hold the mouse button on the pipe near the lower left to examine it and see three red digits: 741. Copy those digits to the box in your inventory and take the U-shaped part inside.

Combine the U-shaped part with the rod from the bed, then use the result to grab the Mr. Birdy (if you can't find it, click the top of the screen after climbing up on the chair seat).

Climb down again and click the chair seat to take it back.

Examine the Mr. Birdy in your inventory. Take the can opener hidden under its hat. Now if only you had a can to open...

Hang the Mr. Birdy on the device on the nightstand. You'll get a green can with a capacity of 600 ml. That won't do you much good, the cup holds 1600 ml and you need 700.

Oh well. Open the can with the can opener and take the triangle key inside. Use that key to open the left cupboard for another can: 1000 ml (still useless as long as it's a multiple of 200).

The can opener won't work this time because the lid's different. Use the coin to pry open the lid and take the palette knife... I mean, spatula.

I just had an idea. Remember the 100 ml hole in the nightstand drawer? Put the clay in it, press it down, then use the spatulette knife to get it back. You've now got a 100 ml block of clay!

Put the block of clay in the 1000 ml can. It'll then hold 900 ml, which is a useful capacity for you.

Fill the steel cup with water if you haven't done so already, then transfer the water to the 1000 ml can. 700 ml will remain.

Now that you've got the right amount of water measured, put the steel cup on the device above the middle cupboard. You'll get a heart-shaped key and a pad for entering four numbers.

You can leave now by unlocking the door with the heart key and sallying out. However, that'll net you the normal end. There's a bit more to do to get the Happy Coin ending...

What could the four-letter combination be? We've seen no letters... although, those numbers on the underside of the chair seat DID look awfully rectangular. Look at 3035 upside-down and it's SEOE.

That worked! Wait a second or so after entering it, then take the Happy Coin that appears. Then unlock the door with the heart key and be on your way!