Settings live on the main menu, before or after a run rather than inside one. Everything saves the moment you change it; there is no apply or confirm step. Click a row, or use ↑↓ and Enter.
Display
Fullscreen — on or off.
Show FPS — puts a frame counter in the corner.
Range Rings — draws each tower's reach on the board. Worth leaving on while you are still learning where a tower's range actually ends, since range is one of the three slots every tower can upgrade.
Audio
Music Volume and SFX Volume, adjusted separately.
Interruptions
Pause on focus loss — pauses when the window goes to the background. It is off by default, and it is solo-only: pausing a co-op game would stop it for everyone.
Identity and language
Player name — the field above the list, and what other players see in co-op. Left blank, the game generates a Player-XXXX name fresh each launch.
Language — sixteen are shipped. English and Czech are hand-checked; the other fourteen are machine translations.
A controller reaches all of this: d-pad to move, A to change a row, and the player-name field opens an on-screen keyboard.