To focus upon this, they isolated three key innovations that they chose to hone in on: the first was the concept of Lara against the world – she'll explore treacherous terrain in the game that very few, if any, humans have been to, and she'll have to react to any threats or hazards that may arise.
Secondly, the team wanted Lara to affect the world and the world to affect Lara. By saying that, the developers wanted to give players the feeling that they were explorers, and that they could manipulate items or elements of the world freely, but in a natural way to help them choose their paths or solutions to puzzles. Finally, the team wanted Lara to be able to do anything players expected her to. This last choice was made so that players had the ability to take chances with Lara as they explored the various pathways of the title, trying different moves or actions that seemed realistic or believable as they made their way through each level. This became more clear as we went into the demo.
To give Lara a hand within combat, the developers gave her a new set of fighting abilities. For one thing, she can knock down enemies with a full set of punches, kicks, knees and acrobatic tumbles. Melee objects, such as poles, can be picked up and swung against opponents. For instance, Lara can use a pole to smack a jaguar across the nose, forcing it to run away in pain. She can also use grenades or her pistols, although she now has the ability to split her focus to target two separate enemies at the same time. This lets her take down multiple enemies at once, or force one into cover so she can then concentrate her fire on a nearby threat.
Along with this, Lara will get dirty from her activities, such as running through puddles or climbing along ledges. This mud will collect and persistently stay on Lara and her clothes, although during the demo, the rain that continually poured from the sky washed Lara clean quickly. (Were the rain to stop, Lara and her clothes would dry as well.) Apart from the clothing, Lara now features more than 1000 physical animations that have been mocapped by gymnasts, and include facial grimaces and smirks when she fires her guns, as well as running and contextual animations. For instance, as Lara picks up poles, she'll use her free hand to push shrubs and other items out of her way as she moves.
The destruction of the floor was based on an improved dynamic physics system that was taken from TR: Legend, and takes advantage of a persistent debris system that continually reflects any damage to the environment. Underworld also includes a complex material system to reflect the moisture or slickness of some environments as they become wet. For example, as Lara tried to climb down into the chamber, her grip slipped due to the stream of water and rain that poured onto the ledge below. Rob had to quickly reestablish her grip to keep her from falling and severely injuring herself. However, this descent into the chamber further showed off new moves, such as the ability to climb and perch onto pillars, as well as firing guns while perched atop these columns. In fact, Lara can even grab onto a ledge with one hand and fire with the other if threats are constantly emerging.