Every senior game players should remember the classic DOS game in those days - Wolfenstein 3D (released in 1992), which is probably the first FPS game you came into contact with (the ancestor of all FPS games that came out even earlier than DOOM, for example: Quake series, Unreal series). I do believe that a number of players just started to like FPS games affected by this game.
Geneforge is a series of nostalgic & fantasy A-RPG small indie games develop by Spiderweb Software (as one of its five representative works) for Windows and Mac OS. The whole game series consists of five chapters (Geneforge, Geneforge 2, Geneforge 3, Geneforge 4: Rebellion, and Geneforge 5: Overthrow), and their story line is coherent but non-linear gameplay with different endings.
Wolfram (AKA: Wolfenstein 3D Remake) is a modern HD remade edition of the classic DOS game Wolfenstein 3D, which was developed by John Carmack from id Software in 1992, and treated as the first game work of First Person Shooter (certainly, as early as 1973, the Maze War born in NASA's PDS-1 computer is the only real originator). It was made by Chain Studios from Russia using the Volatile3D II game engine in 2012, released for free.
Virtua Cop (AKA: Virtua Squad) is a series of first-person light-gun shooter games with 3 works Virtua Cop (1994), Virtua Cop 2 (1995) and Virtua Cop 3 (2003). Virtua Cop: Elite Edition (AKA: Virtua Cop: Re-Birth) is a bundle edition of Virtua Cop and Virtua Cop 2 (along with bonus unlockable artwork) released for PlayStation 2 in 2002.
Army Men II is the direct sequel of Army Men (1998), released in 1999. It used a fire-new graphics engine, accordingly its graphics quality was greatly improved. In stages, it first introduced a variety of new enemies, including cockroaches, and extended battlefields from the "Plastic World" to the "Real World" we live in, such as kitchen and garden.