I'm getting an error that says "Not Implemented" it simply spams this message over and over again.
CONTROLS:
Arrow keys: Navigate the game
Enter or Space: Confirm dialogues or choices.
ESC: Call the menu ingame
F4: Toggle full screen / windowed mode.
ALT is not used to select options. Instead, you can access the options from the game's main menu like seen in the screenshot down below. Maybe there's something wrong with your keyboard?