The old menu was bulky and oftentimes, finding out the information you need was cumbersome. The most impactful are the menus which have been modernized. The moment-to-moment gameplay has not been altered too much but a lot of small quality-of-life improvements have been made. Similar to what we saw in the Age of Empires II Definitive Edition, this game is not a complete remake but a polishing of the original game and expansions. We’re now nearly two decades after the release of Age of Empires III (2005) and have the official Definitive Edition that comes at a time when the RTS genre has been mostly forgotten.