cut my arm with the knife

I can't stop the game being buggy, but I'll now write a walkthrough for anyone who wants one.

Just testing to see if I can get spoilers to work.

WALKTHROUGH

In the screen you start on, pick up the three rocks on the ground near the back wall.

Click on the hole in the ceiling. There is a knife behind it. Click on the rocks in your inventory (which is at the bottom of the screen) and then click on the knife. It will fall to the ground. Go out of this screen by clicking any corner and pick up the knife, which is now on the floor.

Now click under the bed to pick up a battery. I never found a use for this.

Return to the screen facing the door and turn right and click on the toilet. Use the knife on the top of the toilet to prise it off. Pick up the hammer and the box.

Go right to get to a screen facing a wall which has something behind it that glows red. Use the hammer on the crack in the wall. Pick up the gem that is revealed.

Use the gem on the box by clicking on the gem in your inventory then clicking on the box in your inventory (don't ask) to get a note.

Click on the note in your inventory to read it. It says: "the key is deep within".

Click on the knife in your inventory, then click on your hand in your inventory. After cutting yourself open, you will receive a key. If you click anything else during this, you will cancel it and have to use the knife on your hand again.

Use the key on the door.

You're out! (Don't worry, eventually the screen will black out, and you'll have finished the game)

I hope this helps. I dunno if that's the only ending or what, but...