Oh My, so many memories, so many hours spent on this program. Such a fan of MSPaint, thank you for doing this, absolute hero!

Few nitpicks and more of showing off how much I care and love what you've done:

* polygon is antialiasing - it shouldn't * rubber cursor is wrong * circle and rounded rectangle tools are filling their insides when they shouldn't * Text works in zoom mode - it didn't used to (not sure if bug or feature) * Color picker is way too modern :D

But man, even stretch/skew are implemented, awesome job!