post jam version

Since At0 said it was ok to work a bit more on the game today (https://twitter.com/At0mium_/status/1457671845512089602), here is an updated version !

Fixes : 
- Bird animation glitch fix
- Bonus that can lower the speed appears a bit farer and not at the beginning
- The floor is bigger so that it is easier to see holes

Improvments :
- I added a cute trail to Anna when the speed increase
- I added an "Easy mode" so that kidz can play too :)