Homo Erectus's name means "Upright Man," because they were the first ones to stand completely upright. They had bigger brains, and were capable of hunting, fishing and gathering. They were also the first ones to build fires, and while the meat was cooking, gradually became more social. They are often called the "Birth of technology," because they began to make more sophisticated tools that had multiple uses. They were the first to leave Africa and lived from 1.8 million to 200,000 BC, so they overlapped Homo Heidelbergensis and Homo Sapiens/Neanderthalensis. I can infer based on their basic stone tools that they did get smarter than Homo Habilis, but still did not have the free time to make them much better. Also, I can infer based on the video that during their travels, Homo Erectus encountered many difficulties and had to adapt to many different climates, which must have been really hard after only ever being in Africa. Homo Erectus was, as stated above, the first prehistoric human to leave Africa. They spread North and into Asia, and then went East and South almost to Australia.
Sources: Becoming Human video, https://sites.google.com/arlington.k12.ma.us/ehresearch/homo-erectus