Crimson is a medieval-themed role-playing game similar to Dragon Quest. The player controls a lone character, a young man whose father sent him on a mission to defeat the evil monster Crimson before passing away. Exploration is done in an overhead fashion, and is divided into world map and hostile areas, which are usually maze-like and contain one or more dungeons each. In towns the hero can buy weapons, armor, and items, as well as rest in inns.

Enemies appear randomly, and the battles are turn-based. The player character can either attack, defend, or use an item. Combat is viewed from a first-person perspective. Unlike Dragon Quest, there are no random encounters on the world map. Exploration is non-linear, i.e. the player has access to many areas of the map from the beginning of the game.