Thank you for your compliment. For the first version I wanted to get the game play working before adding extra complexity such as animations, changing speeds, number of enemies, and extra enemies (like a crocodile, snake, otter, etc).
I also got the game to work on my pygamer, I had to lower the movement speed. However, with my latest version, I can no longer download it on to the device (Cannot download to PYGAMER). I have also posted an item at the support forum of adafruit (https://forums.adafruit.com/viewtopic.php?f=64&t=170730), hoping that someone can help.