You will earn achievements for completing the story mode on certain difficulties, as well as performing extra objectives. (metalgearinformer.com)
With extra objectives to look out for as you race it's telling that that the one aspect of the game that's least like the original is the most fun. (metro.co.uk)
The game's augmented by RPG - lite elements too, there's an array of weapons, your four favourites can be mapped to face buttons for quick and easy access, not to mention a whole bunch of hidden artefacts and basic health / ammo upgrades to be found by looking in every nook and cranny, ticking off the side quests and extra objectives for each level, and also by occasionally indulging in a spot of actual tomb raiding. (dealspwn.com)