Slayer's Frontier Core Rulebook (Playtest Edition)

From the introduction: Slayer's Frontier is an action and exploration oriented cavepunk-styled RPG based on the 5E Ruleset. With tweaks to the combat actions and skills, bouts of combat flow smoother than standard 5E. Explore untrodden lands, track magnificent beasts, and craft gear to meet with tougher challenges. Teamwork and a good head will be needed to deal with all new monsters!