I'm impressed so far, very impressed. That's all I can say at this moment.

The combat system resembles Batman Arkham series, but not entirely. It's more free flowing in the sense that you can string combos like DmC (the reboot, not the traditional DMC games), so you're not locked to a set string like you would with Batman. This is to say you can string 4 melee attacks into a simple cancel for a manual webshot or something else. But it's not as deep and complex as DMC4 or Bayonetta either.

Combat resembles the Batman Arkham games  from videos because it has a "push button to counter" mechanic and using gadgets to mix things up. The gameplay system does have a little bit of depth to it if you choose to use environments as well, which is what the Batman Arkham games mostly lacks. This is to say most of the gameplay videos you've seen are played by people who hasn't actually explored the game yet and was simply playing it like a Batman clone, which IMO sends the wrong message.

tldr; it's like Batman Arkham, but not really.

I should be done this weekend, I think - unless something comes up.

I can't answer that easter egg question though, sorry.