How to play Uno No Mercy Attack

About UNO: Show 'Em No Mercy Attack, from BoardGameGeek:

UNO Show 'Em No Mercy Attack cranks up classic UNO play with a two-button card launcher and ruthless, hard-hitting rules. Match colors and numbers, then brace for unpredictable card blasts that can crush you in an instant. Press your luck, outlast opponents and don't forget to yell "UNO!" A pitiless game night pick for players ages 7+. NO Show 'Em No Mercy Attack! combines classic color-and-number matching with a card launcher for fast-paced, unpredictable gameplay. Press the Yellow Button when you have to draw—maybe nothing happens, maybe a burst of cards flies out and wrecks your plans. Special cards trigger the Red Button—press and hold to charge up a massive blast that could unleash an insanely brutal flood of cards. Savage rules and powerful action cards raise the stakes, adding chaos, tension and punishing surprises to every turn. Designed for 2–6 players ages 7 and up, this merciless game makes an exciting gift for kids, families and grown-ups. —description from the publisher