SDL Minesweeper

A modern-looking Minesweeper built on SDL2. Anti-aliased rounded tiles, soft
shadows and glows, animated reveal cascades that ripple out from the click,
particle explosions and a procedural sound synthesiser — with no image, font
or audio assets: every shape and every sound is generated at runtime.

Playable entirely with the mouse or entirely with the keyboard:

* Mouse — left click opens, right click cycles flag and question mark,

 both buttons (or a click on a satisfied number) chords.

* Keyboard — arrows, WASD or HJKL move the cursor, Space opens, F flags,

 C chords, R restarts, Esc goes back to the menu.

Difficulty presets are Beginner (9x9, 10 mines), Intermediate (16x16, 40)
and Expert (30x16, 99), plus a custom board editor for anything from 5x5 up
to 40x30. The first click is always safe. Best times per preset are kept
between plays.