Well this game is definitely is "MGS1 but more modern". This description can be applied to almost every aspect of the game, gameplay, story, characters, graphics, etc.

Gameplay is very similar to MGS1's, with a few extra additions:
･ First perspective view is now a lot more important, as it allows you to aim precisely to shoot specific part of the bodies of your enemies. To push you to use the feature, the game introduces a gun with sleeping bullets, more effective if you hit the head of your target. And since there are a lot more enemies than in the first game, you will quickly realize that you have to be really attentive and aim precisely if you don't wan't to get caught! Managing to put a guard to sleep and crossing a room unseen feels definitely more satisfying than in MGS1!
･ There is now platforming in the game?? I don't really understand why they added this feature. You can now hang over the edges of specific platforms, with a gauge telling you how much time you have left until your character looses grip. This part works and I don't have any issue with it. But the second thing you can do is what I don't really enjoy. Compared to MGS1, your character is a lot more agile. You can climb small steps and do cool evasions by doing a cartwheel. This is cool, BUT, the game uses those moves to make you do platforming and it feels very clunky. At one point in the game, you have to cross a diagonal gap by climbing on top of boxes and then performing a cartwheel above the void to jump to the other side. I understand what they tried to make, but the problem is that it is impossible to be very precise with the direction you go to when doing the evasion move, plus the character automatically jumps down when he reaches the end of a platform. So I spend 15 min on an obstacle when it should have taken me 30 sec to pass. But fortunately it is the only time it happened and I think I talked a bit too much about this small issue :')

I thought the double hexagonal level design was really clever! This structure manages to create a playing ground that feels quite small and restricted, while also allowing and favouring exploration. You can always go in any part of the map relatively quickly since its constucted in a loop. Plus, this makes it impossible to get lost, because you will always end up at somewhere you know.

While level design definitely feels better than in MGS1, bosses on the other hand are a bit weaker. But, there still are some really good fights, like the one against Fat Man! His design is so goofy, and his fight is really good. having to both disarm bombs and shoot the one placing them makes for a great fight with good rythm! Quite the opposite of the RAYs boss fight that feels long and repetitive, as you have to take down I don't know how many RAYs that all have the 2 same moves that can be evaded simply by moving in circle...

Story was fun to follow, even if I'm not sure to have 100% understood everything. There are so many twists and people being double agents, but actually they are triple agent, but they are in fact quadruple agent... xD
Raiden character felt like a good protagonist to play after Snake. They are perfect opposite in terms of experience and personnality, so it was interesting to watch his evolution.
Cutscenes are top level, they always felt like a great reward for progressing in the game! And I must say that for a 20 years old game, it looks really good!
On the other hand, the codec chats have a tendency to drag on a little to much. Fortunately (I think?) you can at least play with the cameras framing the characters speaking, so you have something to do while waiting.
And also, the ending cutscene felt strange after all the action and fighting, a very bizarre way to end a game like this.

Music is very intense and it works really well with the gameplay! When you get spotted, you know that you have to fight or die, and the drum and bass stresses that point very well!

All in all, a excellent sequel to an already fantastic game! It is less perfect in every way than it's predecessor, but what it does good is definetly better than what MGS1 achieved.

I played Zelda: Wand of Gamelon and actually liked it, so I figured I could give this one a shot.

This game is more or less the same thing, but with a different map and new levels.
The game let you choose freely where you want to go and figure out by yourself how in what order you have to do things in order to progress. But I felt this one was not as good as Wand of Gamelon with guiding you and giving you hints. I felt I was doing a lot more random things before finding something that worked, and the NPCs gave very vague hints.

Also, the enemy spawn rate feels higher than in WoG, and it gets a bit tiring. Plus there are a lot more traps that will almost kill you in one shot. But since you don't loose any progress when dying, exception made of your position in a level, it's still not a big problem.

I don't have a lot more things to say as pretty much everything I said on WoG also applies here. I got through the game in about 2h, and I enjoyed my time on it!
And since in my review of WoG I linked a remix of a level music, here is one from the bazaar level, made by the same guy!