Eternum is a completely different engine that is a lot faster and makes prediction a lot easier ;)
You also have to realize that just because someone is making a game, they may not be working on it full time. Also, this is not this particular dev's only game. I am fully caught up on both games developed by BM_Rec, and it is exceedingly rare to run into typos or bugs in either of them, which if you play other games, you will realize that in and of itself shows how much bug testing goes into each update. The few times I have actually seen issues in either game, a bugfix is implemented quickly, which shows the dedication to quality work the dev has.