This was heaps of fun, and it looked beautiful. I really loved the pixel art and the colour palette, it looked really effective. You've done a lot of work creating the variety of backdrops, and it paid off. The running animation looked really good. I only got 9 secrets. Was there a map? If there was I couldn't find the button or upgrade. I would've really liked to explore more if I had a map.
Great work. I hope you expand upon it further.