Wizard Fortress

One wizard stands between an endless monster army and the fortress. Hold to launch fireballs, reflect attackers with Karma, burn the five closest monsters with Inferno Slash, or erase a whole wave with Hollow. Charge 1 mana per second: Karma costs 50, Inferno Slash 100, Hollow 200, and Fireball is free. How long can you defend? Face a giant boss every 10 waves with ten times normal health, and target green healers before they restore the army. Defeat monsters for occasional 20-mana drops, and bosses for 100 mana, collected automatically.