World of Warplanes is indeed TERRIBLE. Warships is far better, as is tanks, but Warships is the game of theirs that shines.
This game shares some HUD elements and gameplay with Battlestations Pacific--the oxygen and depths with the subs, as mentioned, but falls just a little short in graphics. More like Battlestations Midway, graphically.
Everything is faster, the ship movement, handling, gun rounds, gun traverse speeds, torpedoes, oxygen consumption (vs BSP) etc. That kind of takes away from it vs. Warships.
I like the subs in there and depth charges. BSP also has torpedo planes too though, so that's still the better game including subs.
Controls are more like Armored Warfare. WASD plus R/F for incremental throttle positions so you don't have to hold W/S.
There are a lot of ships. Feetwet, the South Dakota class is in there, so you can have the Alabama.
If you can read this, these are screenshots of the trees. Anything you see unlocked is there by default, I don't have any real time in this yet.
Haven't figure out co-op yet.