There are quite a few differences between the Middle Paleolithic and Upper Paleolithic periods. While each of these periods did utilize stone tools, there are differences in what the tools were used for and characteristics that helped set the tools apart. Including the different social adaptations that characterized what the tools would be used for and the preciseness of the making of tools in each Paleolithic period.
The Middle Paleolithic period is moreso a period that focused heavily on the evolution of humans, including the introduction of burying the dead, organized religion, and more social organization. Similar to the Lower Paleolithic period, their tools in the Middle Paleolithic period were still stone based. The tool traditions of the Middle Paleolithic period are the Mousterian and Arterian tools, or the “Mode Three” tools. Mousterian tools were becoming more complicated and more adapted, while the Aterian tools were made so that they could be attached to a shaft and used as projectiles.
The Upper Paleolithic period on the other hand is mostly characterized by the Upper Paleolithic Revolution where humans began to use a larger range of habitats, develop stone tools that were better adapted to certain tasks. This created the start of using specific tools for specific tasks. Even crazier is that humans started large-scale trade that allowed resources specific to one location to be distributed to other regions, and began to actually express themselves through art. The different archaeological cultures that existed during the Upper Paleolithic period were the Aurignacian, Gaveltian, Solutran and Madgalenian cultures. These tools were used to hunt larger animals than before and included more precise bifacial blades. While the tools were always created by pressure flaking, the act of pressure flaking became much more controlled which allowed the tools to be more advanced over time. Another thing to note is that due to the advancements in art and self-expression, stone tools were being used to create jewelry which has to be made with extremely accurate tools.
While the two Paleolithic periods do not seem to be very different, being that they both utilized stone to make tools through pressure flaking, the tools of the Upper Paleolithic are better suited to be used with specific tasks and are much more advanced, allowing for larger game to be hunted by humans. The bifacial nature of the tools became much more precise and made for the tools to be much sharper and easier to use than ever before.