That's fantastic to see!

I have many many plans for ProtoSprite haha. Currently it's just time stopping me as asset development is sadly not a fulltime job for me yet.

A flip/rotate feature is planned, it will be quite simple for a first pass though with flip horizontally/vertically and rotate in 90 degree increments. This isn't something that will come in the next update though as that's planned to be a select and move tool for moving a rect of pixels on the sprite. I'd like the rotation feature to be able to work based on the whole sprite/canvas as well as based on a selection so I thought it would be good to make that tool first.

Thanks again for showcasing your work and providing feedback, it's very interesting to see how people use ProtoSprite :)