This post contains some spoilers.
Last week, after I watched Toy Story, I watched Toy Story 2 (coincidentally on the sixteenth anniversary of its release [24 November 1999], just as I'd knowingly watched Toy Story on its twentieth anniversary). I don't think I'd seen Toy Story 2 as recently as I had Toy Story, so there was a lot more that I didn't remember. I found some new stuff too.
This might be obvious but I didn't notice until watching it this time that some of the elements of Zurg's fortress are marked with Zs. When the ground gives way under Buzz, the negative space around the prongs form a Z:
After he drops through, the light shining down also marks out a Z:
The floor tiles (in the foreground below) are hexagons with a Z in the middle:
The second thing I noticed is that when Woody's arm gets ripped, there's a dramatic change in lighting. Immediately after it's happened, before Andy has really had time to react, it's still bright and sunny from when Woody and Buzz saved the day in Andy's imaginary situation:
But once Andy realizes what's happened, it turns dark:
The last thing I noticed was the western flavor of Woody, Buzz, and Bull's Eye's chase after Jessie on the luggage cart at the airport. In many ways, it's like a traditional train car robbery (so in some ways, it's reminiscent of Woody's Round-up from earlier in the movie). They have to catch up to the luggage cart, and Woody has to get from Bull's Eye to the cart while everything is moving, like a bandit jumping from his horse onto a train:
Then, Woody has to climb over three semi-enclosed carts (like train cars) to an open cart (like a tinder car). The tractor at the front is like the engine: