I have jumped on the Unity 3D bandwagon and I have to say, it's a smooth ride. It's refreshing to work in a tool that 100% devoted to game development.I immediately jumped on their 2D platformer tutorial but quickly felt there was too much to wade through. I searched around and found some great tutorials, especially for Flash developers.Unity for Flash Developers (1-7). These will teach you basic Unity concepts and how many are similar to Flash.You have to walk before you can run, but in game development, you have to shoot bullets and make explosions before either. This tutorial will show you how: http://www.unitytutorials.com/video/290/muzzle-flash--raycasting--bullet-explosion1 This tutorial takes you from the start as well and shows great stuff like making terrain in Unity. I haven't made it all the way through this one yet but its the best one have found so far. He uses Cinema 4D (which is Mac only I think) to do some modeling . I just downloaded a 30-day trial of 3Ds Max and everything transferred easily.Unity 3D definitely deserves all the buzz it is getting. When it gets something along the lines of MochiAds I might have to switch over from Flash.