In the first room pick up the bottle on the ground.

Pick up Alice's leg bone as well as the note in her pocket.

Go to the room to the right.

Break the shovel, and then pick up the small rock on the floor.

Go to the right two more times and collect the playing card from the hole in the wall.

Return to the room with the locked blue door.

Use the rock you collected on the bone to sharpen it.

Click the blue door. Use the sharpened bone on the door to pick the lock. Return to the room with the chest, it is now open.

Click the chest. Go down.

Use the bottle on the tree trunk filled with acid.

Use the acid filled bottle on the web protecting the caterpillar.

Use the broken broom handle on the sticky sap.

Combine the sap with the broken shard of glass.

Stab the caterpillar.

Pick up the key.

Go to the locked tree door.

Use the playing card on the slider, and then the key on the door.

Click the door.

Click the briefcase.

To find the combo, return to the room with Alice's body.

Use the lens to view the writing on the wall.

The combo is the order that the numbers appear starting in the room with Alice, and going right.

The combo is 829 203.

Enter the combo in to the briefcase.

And you win.