I figured it out! The way I did it was that I first made the magenta side, then I filled in the light pink. I knew logically that after I did the light green the dark green would be done. So I did the light green and completed it. I found myself using R U R' style inserts to solve the light green, so I would say cubing helped, at least somewhat.
By the way, I would love to see this as a mobile app. The two things I don't like about it are the color choice and the way you turn the puzzle.
To deal with the first issue, I think you should use "softer" colors that don't hurt the eyes. For the second issue, I found it annoying having to turn the sides 4 times to do one move. A cool mobile feature would be the ability to swipe left and right to turn the sides clockwise and counterclockwise.
As for other suggestions/features, obviously for a full-fledge mobile app there would need to be more levels. I honestly would make a fair amount of the levels easier than level one. This could most likely be done by using a smaller size puzzle with less pieces. I also think there should still be a fair amount of levels harder than level 2, which could be done by using a bigger puzzle with more pieces. I would also love a timer mode where you try to complete it as fast as possible.
Overall, this prototype has huge potential and I can't wait to see where you go with it. Best of luck!