A Stealth-Based Game
is a game wherein the primary focus of play involves sneaking around unnoticed, rather than fighting. However, not all stealth games are created equal. Some enforce realistic combat physics on the player, making stealth more viable than failed attempts at action movie stunts. Others strip the character of any useful ability to fight, or even any ability to fight at all. On the other end of the spectrum, the player might be perfectly capable of fighting it out like in a normal action game; the game merely discourages this by providing more interesting options elsewhere. Thus do stealth games land on a spectrum.
Type 1: "Helpless". The player has no combat capability at all. If stealth fails, you either instantly lose, or you might as well.
Type 2: "Realistic". The player does have the ability to fight, in a manner appropriate to the setting. However, their capacity to do so is relatively limited, often not moreso than the typical enemy in the game. As such, stealth is heavily favored for its ability to avoid being outnumbered or taking an unlucky bullet.
Type 3: "Aggressive." The game's mechanics support an action style of play, with extensive cinematic capacity. It may be possible to completely ignore stealth largely or entirely and still play the game successfully, though this likely will involve missed content. Alternatively, there might be specific circumstances where stealth is still necessary. The key element is that non-stealth is not punished, as in the above types, so much as stealth is rewarded.