🧑 Player — 1 HP, moves 1 cell (↑↓←→)
🧟 Zombie — moves up to 2 straight or 1 diagonal toward player
💣 Bomb — Space / tap player to place. Explodes after 2 player moves (✚ 5 cells). Kills zombies & destroys obstacles. Player in blast = death!
🚪 Door — exit (locked on level 3+)
🔒 Locked door — needs 🔑
🔑 Key — unlocks the door
⬛ Obstacle — impassable cell