How does Unity compare to something like CoronaSDK for 2D games? Unity clearly seems geared more towards 3D gaming, but I've seen some references to locking the Z-axis to create 2D experiences.
There a lot of plugins to handle 2D (2.5D) games on Unity, I am currently using 2D Toolkit ($50) for sprites and it's awesome. I also recommend to check RageSpline and RagePixel, this tools provide features totally integrated with the IDE and really easy to use.
I haven't try CoronaSDK but I can see a lot a potential in 2D games with Unity, not just 3D. I fact, you can see a lot of nice 2D games in his showcase, for example Zombieville USA and Max & The Magic Marker.
Unity is really not less than a total 3D environment for developing games .. you can definitely use it to do 2D style games (or 2.5D games, where 3D models are locked on the Z-axis, as you say) but in my opinion if you want flat bitmap-style 2D games you'd be better off getting into something like MOAI (http://getmoai.com/) or Corona or LÖVE2D to get the job done .. (my pref is MOAI right now, its just so fresh and fun..)
