Use the autoformat function of the IDE to nicely format your code, and make it more readable.
Use the F() macro for string constants (like you use in the print statements), saves your scarce RAM.
Lots of delay() statements. That will make your buttons far less responsive than they should be, as nothing gets done while in a delay(). You can get rid of them by turning your code into a finite state machine and using millis() for timing.