Sans the graphics, this is a very immersive game with customization elements.
The game has a ton of customizable parts. About 1500 parts for you to find, research and equip.You can literally spend 30 minutes to an hour just customizing your ship (or battleship in my case), figuring out what is the optimal weight or weapons displacement for your ship.
This is a very hard game, even on normal the game can pack a punch. I literally had to play on very easy just to pave my way through on my first playthrough.
Game longevity wise, there is quite a bit. 3 different storylines to unlock (be very careful, you probably would need to use a guide to find out how to unlock them since the storylines deviate very very early on the beginning depending on what you do in the first few missions). And there are also extra super hard missions, time attack, even straight up boss run battles.
The game is one hardcore warship simulator, and this game just goes to show that the ps2 still has some of the best games out there.