Earlier quoted context omitted.
Nice! Small nitpick, as a Dutchie: we changed the shape of our country quite a bit over time by reclaiming sea. The map of the area now occupied by The Netherlands was very different two thousand years ago from what your site shows. (And this had geopolitical consequences, e.g., the invading Spanish could not cross some of the bodies of water present in the sixteen hundreds that are not there now.)
The German coast also had notable man-made changes, though far less extreme than what the Dutch did
Which means that - Congratulations! This is only the beginning! There is so much to add, both in granularity, a year is not enough during some events. But also when it comes to geography. Or why not integrate it with google maps, to get an even more precise granularity in the 2000s when all of this accelerates.
But it is very impressive and a huge time sink to be mesmerized by!