First off, what an amazing game!
This might just be me, but I’m a huge fan of fast paced combat. I think the default ship should have faster paced combat.
For reference, the sting ray is a sniper and has a 15 second mag reload (its the default). The other starter ship is the sail fish, which is a melee battle ram ship.
This kind of goes into retention too, but I think your starter ships should be incredibly easy to use. It’s not by coincidence that most FPS games start their players off with AKs and other weapons with high fire rates and versatile ranges. The string ray, while pretty OP, isn’t very intuitive. It’s gun isn’t very responsive and it has a long reload.
I think making the default ship some sort of rapid* fire ship with a responsive turret would be good (even if you make it not nearly as good as the other starter ships).
* like ~6 rounds ~3 second mag reload
Another thing I saw in game, new players don’t like being stuck with no moving parts.
For example, I hit someone’s motor and gun, so they were basically a sitting duck. I couldn’t attack them though, since I lost my ram and was waiting on a 15 second reload. The player left before the reload was done.
I think that when a player’s ship has lost all of it’s active parts (motors, guns, etc) a UI should pop up asking the player if they’d like to respawn (or just some text telling them the key to respawn)(especially for new players).
Just to reiterate though, your game is absolutely amazing! The UI is incredibly well done and animated so smoothly. The controls and general physics work really well too. Your game has a ton of potential.
Edit:
Something else, I think starting players off with enough credits to buy something (or, maybe even better, be close to buying something) is a good idea too.