Naval Thunder presents the basics of naval combat in a very easy-to-play format. Ship movement is simple to learn and play, but at the same time it captures the essence of the critical factors in changing range, speed, and direction.
Gunfire and torpedo attacks are nicely tailored to range bands which differ by ship class and gun type. Hits and resulting damage are straight-forward, with the excellent twist of Critical Damage. This accords well with my view on naval combat in the WW2 era - sometimes a ship would take a number of hits that do little damage while at other times one or two hits doom a ship. Some damage, such a fires, flooding, and listing, can extend across turns, gradually wearing down the ship's resistance to further structural damage.
A nice plus to the Critical Damage resolution is that offensive and movement capabilities do not degrade in a straight line. So a cruiser might have very heavy hull damage, and in danger of sinking, but the entire main battery may still be functional. There were certainly examples of this during the war. Conversely, it might be necessary to pull a battleship out of a fight (or attempt to) because several main battery turrets have been knocked out long before the ship is in any danger of sinking.
We've fought a wide variety of actions with Naval Thunder from battleline meetings to small ship skirmishes, including night actions in restricted waters, and the results have always been quite believable. This factor, in addition to ease of learning and ease of play, make Naval Thunder my top pick for WW2 naval gaming.