Adjustable difficulty

[ekinkaradag]

Is your feature request related to a problem? Please describe.
It would have been really nice if the user was able to change the size of the grid and/or the speed of the snake

Describe the solution you'd like

• Display 4 radio buttons for difficulty (the first three will have predetermined grid size and speed of the snake values:
  • Easy
  • Medium
  • Hard
  • Custom
• If the user clicks on "Custom":
  • Display a slider for the grid size
  • Display a slider for the speed of the snake

Describe alternatives you've considered
Only display two sliders. One for grid size and one for the speed of the snake