Features

Many components category: powerplants, battery, capacitors, engines, warp engines, radiators, fuel tanks, cargo bays, gyroscopes, sensors, crew quarters, armors, turret engines, warp disruptor, shields, fuel pumps.

Realistic weapons:
Cannons: use an explosive charge to propel munitions. Cheap, with high firepower and low power usage,  are also versatile with many munitions types: AP, HE, Sabot, HE-AP, Flak, HP, Frag.
Gaussian Cannons: uses electric energy to accelerate a projectile to high velocity.
Have longer ranges and better armor penetration than conventional cannons but uses high amount of energy.
Lasers: never miss, have the longest range, good armor penetration but low firepower.  Very good as point defense weapon. Diffraction limit is simulated, and when the distance with the target increases a larger part of the energy becomes heat instead of damage.
Missiles: Very destructive if they hit but are expensive and can be disabled before reaching the target or may run out of fuel.  Can also be used to intercept enemy missiles. From the point of view of the simulation engine, missiles are just small ships and like them are made of components that can be damaged indipendently. Their AI does not cheat and use the same newtonian physic like bigger ships.

Damage simulation:
Each component and armor section has his own hitpoints and hitbox.  The trajectory of each bullet inside the ship is tracked and each component and armor section hit is damaged until the bullet is slowed down enough to stop. Armors are stronger than regular components and can stop bullets and explosions without being damaged if they are thick and hard enough. You can use the in-game tool to select the best armors and munitions for your ship.
For example, a HE-AP shell with delayed fuze could penetrate your armored hull, travel a few meters, reach the innards of your ship and then explode near an ammo container. This could trigger an explosion of the ammunition and destroy all nearby components.

Ship customization:
Every decision you take while customizing your ship can make the difference between victory and defeat. You have a budget and ships have a limited number of slots of differents sizes.
Each component you add increases the mass of the ship and decrease accelleration and warp speed.
Add more fuel tanks for your engines or extra batteries to power gauss cannons?
More engine to increase combat accelleration or more warp engine to outrun enemies? Heavy armor to stop small weapons or light armor for more agility and better avoid being hit? A powerful short range gatling gun or a laser to snipe enemy from afar? What is the most important component to mount in the well protected inner slots and which one is expendable and can be used to shields components behind it?
The space yard where you are refitting your ship might not have all the components you need and you have to build the best ship you can with whatever you have available while you find better stuff.

Newtonian physic:
Every ship has mass, center of mass and moment of inertia calculated in real time based on mass of components installed and armor. Recoil and collisions with ships and bullets cause effect on velocity and angular velocity depending on the location of impact.
Ships are affected by gravity field of planets and stars.

Real scale:
Planets and star systems have realistic size and distances.

Sensors:
You need sensors to detect ships. Each type detect a specific emission: warp sensors detect ships that are traveling using warp engines, thermal sensors the heat emitted from radiators and engines.

Ship management:
You have to manage ship resources: electrical power, fuels, heat, ammunitions.