Got the game world right: * Half-Life series * Deus Ex 1+2 * No One Lives Forever 1+2 * GTA San Andreas, GTA IV * Mafia 1+2 * System Shock 2 * Thief 1-3

Got the game world right: * Half-Life series * Deus Ex 1+2 * No One Lives Forever 1+2 * GTA San Andreas, GTA IV * Mafia 1+2 * System Shock 2 * Thief 1-3 * Black & White 1 * Far Cry 3 * Tomb Raider (2013) Player can interact with the game world, destroy things (many small items), the environment remembers your action (e.g. opposite-sex bathrooms in Deus Ex 1 and No One Lives Forever 1), some funny moments, ... IMHO bad examples are Deus Ex 3 with its very static game world, Assassin's Creed with its limited interaction options, many role playing games like Gothic series, Elder Scroll series (Morrowind, Oblivion, etc) were you can steal from all NPCs and their chests and no one asks/follows you, Call of Duty series with their unlimited AI enemies(if you stay and wait), etc.