Kojima has stated that with the PlayStation 3, he will be able to focus on the things we can't see, and to explore the senses that videogames rarely tap into. For example, if a building is severely damaged, the resulting sound from a nearby explosion could cause the building to crumble and fall. Furthermore, he is planning to consult psychiatrists on how to emphasize a "mental battle" between Snake and his enemies, so that "who controls the fear can decide the outcome".

http://www.gamespot.com/ps3/adventure/m ... Ot5bsEsz_c

The First ever Gameplay footage for MGS4.