The Summoner's Bell

#LDJAM (Ludum Dare 36 entry by Linear et al) Deep within the reaches of a far castle, a bell rings, summoning ancient mechanical horrors with its foul knell. WASD moves, right click to shoot bolts. Pick up keys to unlock doors. Every time the bell sounds, more monsters spawn, so hurry to the next area before you get overrun! Game is over when you destroy the bell.