I don't know if it's my computer, but when I played there was a lot of lag when I was in open world scenarios and when I was fighting.
We're currently optimizing the game fully but it will take a few weeks until we release a fully optimized version. So right now it is particularly heavy even on stronger machines.
You could share your PC specs here if you don't mind, so that we include it into our optimization list. Sorry for the inconvenience!