Is your Snake Solid for some more Metal Gear?
The story remains completely unchanged from the original. You're still Solid Snake, sent to infiltrate a nuclear waste disposal facility known as Shadow Moses. Along the way you'll rescue hostages, fight overblown boss characters and of course fight the obligatory Metal Gear. Broadly speaking, the story is still good at what it does, providing twists and turns in equal measure, which keeps it enthralling throughout. Unfortunately most of the acting performances fail to reach the levels of the original, falling very much into the stock video game voice acting cliché.
Whilst the story may have stayed the same, individual cutscenes have seen significant changes. Snake is now a much more superhuman soldier, backflipping in slow motion to avoid bullets that he would have previously just dived out of the way of. It would be easy to claim that these ruin the seriousness of the story, but these claims are only really valid in comparison to the original. Newcomers to the series shouldn't find anything out of place with these cinematics when put next to a boss that will happily read the contents of your memory card to break the fourth wall.
Snake appears to have done some training since his last stint on the island. Railings and lockers that used to be about as useful to him as 'Baby on Board' signs can now be jumped over and used to hide enemy soldiers in respectively. These new abilities alone can provide very different routes through areas that many MGS vets will know like the back of their hands, and as such are at the very least a useful addition to Snakes arsenal of moves.
The problem is that although Snake has all these new moves at his disposal, the environments in which he can use them are fundamentally the same as in the 1998 original, they simply weren't designed with these actions in mind. Combine this with improved enemy AI that allows the guards to notice you when you're outside of their cone of vision, and the ability of Snake to shoot in first person, and you have some levels that feel unreasonably difficult, and others that turn into a bit of a cakewalk. Puddles that would have previously provided background decoration now alert the guards aurally to your presence, and boss fights that revolve around you chasing them can now be circumvented with some nifty first person aiming. It's not broken per se, it's just not optimised.
Ultimately however, you're simply not going to notice these things if you've never played MGS before now, and if you have there's enough nostalgia here to blind you to their presence. The Twin Snakes may not be as good as the game it tries to copy at every turn, but it comes close enough to warrant a good look.