The best thing about grit was its flexibility to create different types of scenes (or what I call 'worlds'). You can make your own worlds or use something like Unity's built-in scene editor which has tons of prebuilt assets already made by other developers who know how things work in this kind of environment! As far as performance goes - it works really well even when there are hundreds/thousands objects spread across many tilesets without noticeable slowdown at all thanks goo much GPU acceleration support through Metal API implemented natively into OS X! There were some issues while trying out new features using their online demo app but nothing too catastrophic thankfully so no need to worry if you're just starting off :) Definitely give them another try because they've got lots going right now including major UI overhaul coming up soon!! Also great community supporting everything from tutorials written down step by steps available openly over github repo etc!! This helped me understand shader programming better than any book could offer otherwise :).