Al college sto facendo un incarico sulle differenze tra i requisiti (non) funzionali. La dichiarazione del problema è la seguente:
Space Invaders is a single player game. After starting the game, the player selects a level of difficulty and starts playing the game. The player can steer a space ship to the left and to the right and can also shoot rockets. The goal is to destroy invaders. If a rocket hits an invader, the invader disappears and a crash sound is played. A game is finished when all invaders are destroyed. In this case the elapsed time for destroying all invaders is displayed. Each player has a personal score which can be compared with other players of the game. While the game is running, music is being played. The game can be paused, in which case the timer stops and the music stops playing. During the game, the player can always see the elapsed time and a counter of the destroyed invaders.
Per quanto comprendo la definizione, tutti i requisiti specificatamente elencati in questa dichiarazione sono funzionali e non funzionali non specificati (disponibilità, stabilità, ecc.). Qualche idea?