Heretic is the Retro Game of the Day for 25 April, 2016

From Wikipedia:

Heretic is a dark fantasy first-person shooter video game released in 1994. It was developed by Raven Software, published by id Software, and distributed by GT Interactive. The game was released on Steam on August 3, 2007.
Using a modified version of the Doom engine, Heretic was one of the first first-person games to feature inventory manipulation and the ability to look up and down. It also introduced multiple gib objects that spawned when a character suffered a death by extreme force or heat. Previously, the character would simply crumple into a heap. The game used randomized ambient sounds and noises, such as evil laughter, chains rattling, distantly ringing bells, and water dripping in addition to the background music to further enhance the atmosphere. All of the music in the game was composed by Kevin Schilder. An indirect sequel, Hexen: Beyond Heretic, was released the following year. Heretic II was released in 1998, which served as a direct sequel continuing the story.

Not only is this game one of my favorite FPS games of all times, it has probably my favorite FPS weapon of all time: the Gauntlets of the Necromancer.  Sure, it’s a reskin of the Doom Chainsaw (as are most weapons and monsters in the game to some extent), but the sound effect, the visual, and the awesomeness of what they bring to the game is just incredible.  Add an inventory system to the cool medieval aesthetic and you have a solid, fun game that everyone should play.