when climbing out of the pit, it was very easy to immediately fall back down (due to the pixel-perfect collision detection).

And here is an excerpt from the manual: “Even experienced extraterrestrials sometimes have difficulty levitating out of wells. Start to levitate E.T. by first pressing the controller button and then pushing your Joystick forward. E.T.'s neck will stretch as he rises to the top of the well (see E.T. levitating in Figure 1). Just when he reaches the top of the well and the scene changes to the planet surface (see Figure 2), STOP! Do not try to keep moving up. Instead, move your Joystick right, left, or to the bottom. Do not try to move up, or E.T. might fall back into the well.”