When Zach chases Walt to get the pouch from the Turtle's lair back, Walt has it in his hand. When Walt comes out of the manhole with Zach behind him, he's holding a piece of paper. Then, when Walt arrives at the stage, he has the pouch in his hand.
When the Shredder pulls the lever to stop the Technodrome from entering the lava lake, the eye on top of the Technodrome is missing as soon as we see it stop.