Minimum size: 60 columns x 20 rows — the menu screens fit themselves to the height available, giving up spacing and then the per-mode descriptions rather than dropping a line off the bottom.
In the browser: the same 60x20 is the floor, and the page shrinks the font to reach it rather than letting the grid overrun the window. A window too small for 60x20 even at the smallest font shows a "Window too small!" notice instead of the game, as the CLI build does in a terminal it cannot fit; the run is left where it stood and the engine hum stops with it, so resizing back brings the same game up.
Color support: 256-color ANSI (most modern terminals)
Unicode support: Box-drawing and block element characters
Recommended terminals: Windows Terminal, iTerm2, GNOME Terminal, Alacritty, Kitty