Many players consider the Madness and Injury cards included in Dunwich Horror to be a vital addition to the game. Personally, I find the Epic Battle variant in Kingsport to be an even more enjoyable and essential ingredient than the Dunwich cards.
The Kingsport rulebook states that the Epic Battle variant is intended to provide a more exciting and challenging battle when the Ancient One awakens, and it accomplishes this goal beautifully. It also adds a great deal thematically to the final fight. Finally, the Sinister Plot cards are a stroke of genius, individualizing each AO with interesting special attacks. Just as I can't envision playing the game without the Dunwich board, I also can't envision playing it without the Epic Battle variant.
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