Nice platformer. Performance could be better tho, it feels laggy, higher fps thus more fluent gameplay would make it more enjoyable.
I love the graphics, they are simple, but have nice colors to look at and remind of mario.
Missed some BGM. Music and Sounds are important and a well chosen background track can improve the game so much.
Flags, once triggered, should stay down, else the map is like a labyrinth and you can get lost. Or maybe was that intented?