I’m surprised that the developers of this game haven’t posted here yet. Their game which just came out yesterday on Steam is generating a LOT of love and positive exposure from both gaming ‘press’ and players. And I confirmed with the devs this morning on twiitter that it is indeed done in Unity.
WTF is Ironcast - Totalbiscuit:
Rock, Paper, Shotgun: http://www.rockpapershotgun.com/tag/ironcast/
Just Press Start: Just Press Start - Blog
Ironcast website