OK, there is room to grow, because this is too great an app to be static, and because the whole execution of the concept is so well done, that I cannot imagine the creators aren't still coming up with more ideas, at this very moment.
I made my living as a designer, painter, art director, and all I can say is HOLY COW, this is brilliant, original, and delicious!
I would like to believe that all the years I have been training my eyes have been worth something, and it breaks my own rules to buy an app that stylizes so strongly... however... really, this is a wonder!
Surprising variations are possible with great options, perfect color choices, and text tools. Results are similar to letterpress in feeling, This won't replace any apps you already have: this is a whole new point of view.
I found Retromatic20, today. It is terrific straight out of the box, or pulled through other art/photo apps. The UI is straightforward. I found myself discovering possibilities, while muttering under my breath, "Good job!"
It would be useful to be able to save and/or import separate transparent layers. A mask erasing tool would be good. More of everything here would be fabulous, but really, it is perfectly smashing, as is. I bow in respect, to the developers for their originality, brilliant design sense, and refreshing whimsy. Bravo! Forge onwards! I can't wait to see what you think of next!