Speed completion – Technically 4,000 frames. Actual time may be more or less than 4 minutes depending on your processor speed. Keep an eye on your "best so far." Note that this game typically runs best in IE. [Best so far: 4064]
How to beat cave 5 - Use Units- Witch, Centaur, Black Knight, Succubus, Goblin, Mermaid, Use Spells - Healing, Phoenix Bird, Hercules, Athena, and Arrows. Just keep hitting forward. When your mass army is at the front of the castle and you hear the first ring, cast Athena on your melee units and Hercules on your ranged units. Use phoenix and arrows when you have less troops and want to clear out the way. Re-post if getting to the bottom. Thanks for the comment!