The most interesting part about Retrica is the pile of filters available, accessed in the bottom-right corner of the interface. You can hit a shuffle key to randomly pull up a filter (I honestly don’t see much use for this one), or choose one manually. Filters are grouped into themes like “chic,” “silver” and “cinema” with each one containing several different filter looks. You can tap one and see your viewfinder change immediately to reflect what the finished product will be, and use a slider along the bottom to change the intensity.
And that’s about it. The fact that you get a live preview of what your picture will look like in the viewfinder is the real draw here, and it’s an important one. I never noticed any slowdowns while the filters were being shown, which would be a deal breaker, and pictures turned out just as they looked before I hit the shutter key.