Act 4 is pretty great!

I really like how Act 4 is structured. It paces really well, the exploration opportunities are fun. The mob density is fun. The locales are interesting. Overall it's pretty great and I enjoyed playing through it a lot. Not sure about the bosses because I didn't really pay attention to any of the mechanics (minions).

I just wish the rest of the game was this fun. Act 1 is fairly boring, Act 2 is okay, and Act 3 has got to be one of the worst acts I've ever played in a video game.