Creaks

After the room with a conga line of shadow dudes in it, you'll pass through a tunnel underneath it. The painting is here, it's very hard to miss. It's the 32nd scene on the 'load scene' screen.

To complete the painting you'll need to shoot the waves of bugs before they reach the two . Right and left on the left stick moves the guy on the right's gun up and down respectively. Up and down on the left stick moves the guy on the left's gun up and down respectively. fires both guns. You can fire quite rapidly, so just blast away. I found it easier to concentrate on one side and then the other.

Confusing scene numbers
If you’re loading a scene from the ‘load scene’ screen on the main menu, note that I’ve counted scenes from the first that’s highlighted by default (the long descent by ladder into the underground world). There is also the prologue, but ignore that when you count the scenes. For reference:

• Scene 10 is the bright room with a big tree in the middle
• Scene 17 is the room shaped like a birds head with a stained glass window for an eye
• Scene 24 is behind a huge clock-face
• Scene 39 is the cable car
• Scene 46 is the giant broken hamster wheel