Message indicator is similar to Reddit, top right of page next to your username. It's not super noticeable because it doesn't contrast to the red background, but it's there. White when no messages, orange/red when messages are new.

Downvoting, among some other bits of polish, would be nice I agree, but for a brand spanking new site constructed in secret it's looking pretty damn good.

It could use some polish but I'm impressed with what has been done here