The gameplay of Horace primarily features action-adventure and platform game elements, with guided non-linearity as well as utility-gated exploration and progression typical of the Metroidvania subgenre.

Acquiring key items or ability upgrades for Horace enable players to explore areas that were previously impossible to reach.

These waste items represent the game's collectible system, which provides an incentive for players to thoroughly explore the in-game world to acquire achievements.

Three years after the development of Horace commenced, Helman received some assistance from programmer Sean Scaplehorn, who helped create a game demo for a conference in London which drew the attention of some publisher representatives in attendance.

[2] Some of the major influences for Horace included Helman's past work experiences with the Die Hard Trilogy as a one-time employee of Probe Entertainment; the development of a video game called Boom TV which was eventually canceled as a result of the September 11 attacks due to the presence of the World Trade Center buildings as a destructible environmental element; and the sights and surroundings of the industrial town of Sittingbourne where Helman resides.

[2] The scope and scale of the Final Fantasy role-playing game franchise informed Helman's desire to make an "arty platformer" which gradually expands into a sprawling in-game world.

[5][6] On November 28, 2022, Paul Helman received the Love Story Gaming Award for Excellence in Storytelling for his work on Horace.