I really like the concept, so I'd like to share some impressions:
- I love that the menu and the tabs are vertical. Since a lot of sites just having empty space on the vertical edges anyway this makes a lot of sense to me.
- The new tab button really need to be near the tab list (or at least duplicated there).
- The two pane view is great, but I would like a quick way to choose in which pane a tab opens when I click it. I think an intuitive way would be for left click to open it in the left pane and right click in the right.
- The media player is fantastic. Love the always on top floating video option.
- I like how the design uses my desktop background as the background.
So good job on the concept. I hope it is developed further, and/or that opera moves in this direction. If this browser had extensions I would switch to it in an heartbeat.