[Not Steam] Free - Desperados: A Pen and Paper Roleplaying Game

Download link: https://www.drivethrurpg.com/product/316116/Desperados-A-Pen-and-Paper-Roleplaying-Game

You just need to sign up and you can checkout the game for free.

Description (taken from the website)
The countryside passes by without the least sign of change, accompanied only by the wheels’ monotonous rattle on the rails. Noon has come; relentlessly the sun is blazing down from high above. Then, the eye distinguishes a solitary horseman on the horizon, and only a few seconds later a second one. From both sides, more and more horsemen are heading towards the train.

Welcome to the world of Desperados. Based on the award-winning video game franchise, this classic tabletop RPG aims to combine the best of both worlds: the challenging, tactical encounters of Desperados III and the freedom of choice and immersion one can only achieve with pen and paper.

The Wild West is a dangerous place; only the best will live long enough to give rise to their own legend. This PDF contains everything you need to become one of them:

• An illustrated rulebook
• A complete, first adventure
• Printable character sheets, maps, and tokens

One more thing! You can play the latest Desperados 3 demo for free on GOG: https://www.gog.com/game/desperados_iii_demo :)