[6] The game also takes advantage of advanced artificial intelligence to respond realistically to noises and light, creating stealth-based gameplay.

There are no firearms in the game, so during combat the player is limited to improvised melee fighting with a hammer or pickaxe,[7] or throwing objects at attacking creatures.

Environmental objects such as doors, desk drawers, and switches on machinery must be opened or manipulated using realistic movements mirroring their use in the real world, and certain obstructions can only be cleared by utilizing certain objects in a specific way; for example, in order to solve one of the game's puzzles a player may choose to stack boxes and barrels in such a manner as to allow for the player to be able to leap past an obstacle, such as an electrical fence, or to reach a certain area normally too high to reach.

Essential to puzzle solving is the ability to read written notes scattered around the mine by its previous inhabitants, which often offer clues or solutions as to how to get past a certain area, as well as providing plot exposition and character development.

Within the mine, Philip discovers diary extracts written by a stranded scientist who gradually resorted to eating cave-dwelling spiders as an alternative food source as his supplies diminished.

The scientist also describes discovering a psychoactive toxin in the spiders and deduces that, after eight months of using them to supplement his diet, it was beginning to have an effect on him.

Philip begins to receive radio messages from Tom "Red" Redwood, a man driven insane by cabin fever.

Philip quickly discovers that the mine is inhabited by an ecosystem of abnormally large and hostile animals: dogs, giant spiders, and gargantuan earthworms, among others.

With no other option, Philip activates the incinerator and, amongst Red's remains, he finds an item that he needs in order to progress into a new area of the mine identified as "The Shelter".

On 10 January 2008, the full version for Mac OS X was released on the Frictional Games forum for PowerPC and Intel architectures.

[18] It was criticized on a number of fronts, especially for its rather crude combat system and sometimes confusing or poorly implemented story elements, causing Eurogamer to comment that the game would "do better if it relied on its own inherent spookiness rather than trying to create artificial atmosphere by banging on about a character we don't have any real reason to care about, something about his dad, destiny and miners writing stupidly long notes to themselves about their imminent horrible deaths".

[21] GameSpot in its review commented on the combat by saying that fights are often "so frenetic that it's almost impossible to control your movements" and that "it would have been much more sensible for the camera to lock on and move with enemies".

It did however note that it did help differentiate Overture from more action oriented titles, saying that the "end result of the difficult combat is that you feel like an average Joe who wants to avoid zombie dogs with glowing eyes, not a video game superman out to stack dead canines like cordwood".