Ashley - yeah maybe, I don't really know enough about it. Tested on multiple low-end pc's and laptops and the performance just isn't there, We actually did a live stream with the Area5 / Outlands guys and the game ran really bad on their machine, this is what made us switch engines. So far in Unity it's screaming fast.
There could be many reasons as to why, but we've extended Unity so that we have similar 9-patch functionality and for whatever reason putting the textures onto polys and scripting in c# makes for crazy speeds in scenes with identical complexity between engines.
As i say though, C2 is still my go-to 2D engine, just that for whatever reason Orbit wasn't right for it, could have been bad scripting in events on my end, or it could have been trying to render too much or something like that.