TSVG: Tactiacl Shooter Video Games are games that by definition simulate a more realistic form of combat and hence relying more on strategy and stealth as opposed to relying on button pushing, quick telexes and fast actions. They can be FPS or TPS games and pretty much the genre is split. What really defines this genre is the realism, in these games you can, and will die, from one (critical) bullet shot. The weapons used are also one of the factors defining the genre. In these type of games the weapons are modeled, typically, on real weapons and thus the amount of customization and upgrading is often minimal at best. The ability to attack is also limited, often the ability to exact critical hits is based on your position, the environment and your ability to aim accurately. Much more emphasis is put on achieved a superior position and being able to target the enemy and more often than not running, jumping and rush attacks are actually not beneficial. The first true TSVG was Seal Team (released by EA in 1993) although the break-out game was probably Delta Force (released by MS in 1998). The next evolution which marketed the game to a wider audience was undoubtedly Rainbow Six (released by Red Storm Entertainment for the PC in 1998 and eventually ported to PSOne, MAC and the Gameboy Advance). To date the genre, other than the Rainbow Six series is limited to diehard fans and has yet to have a break through game in next-gen consoles
TPS: Third Person Shooter shooter games are games which by definition revolve around your controlled character being visible onscreen and the gameplay focusing on a shooter type game. These games are sub-genre of action games in which the viewpoint is over the shoulder and typically the damage and ability to be successful is determined by the accuracy of the shot as well as the ammunition used. The genre is very closely related to FPS's but because of the ability to actually view yourself it typically allows for slightly better graphics. You are also able to see the surrounding area of gameplay better and it is typically a more strategic battle as well as the interaction between the player and his/her obstacles is not only more easily defined but easier to navigate due to the viewing perspective. The expanse of the perspective also allows for a much wider gaming world to play in not necessarily in levels but in the amount of larger and more spacious rooms/landscapes etc. Many believe the first true TPS to be Fade To Black (released by Delphine Software in 1995 for the PSOne and DOS) although there is some argument that Tomb Raider (released in 1996 by Eidos Interactive) certainly was the first game to actually really popularize the genre. The next "big thing" was Syphon Filter (released in 1999 by Eidetic for the PSOne) which combined earlier elements into one game. The genre really gained ground in 2005 with the release of Resident Evil 4 (released by Capcom for the pretty much everything, lol) which provided ultimate camera control and introduced a new system of interactive controls to manipulate the landscape/buildings, ladder, fences, trees etc. The genre continued to grow with the release of Gears of War (2006 by Epic Games)and Batman: Arkham Asylum (2009 by Rocksteady Studios) and continued with Resident Evil 5 (2009) and to date the genre is alive and thriving.