It's the sort of game I've been wanting for a long time, a (simple but functional) 4x where you design your own units
The design process is simple enough to be accessible but complex enough to involve meaningful tradeoffs and compromises. Armor makes a ship sturdier but slower, heavier, and more expensive. Big guns can inflict monstrous damage at long range but they are likewise heavy and expensive and eat a lot of ammo, which means more ammo storage, which takes up space and can explode if hit. Soldiers have to move around the ship to do things like fuel engines, put out fires, and reload cannons, so you have to keep traffic flow in mind and try to avoid situations where e.g. a single destroyed corridor effectively makes an entire section inaccessible.
Pictured above is my latest design, the Dreadnought, a monster of a ship with four heavy gun turrets and a thick coating of steel armor. It costs a fortune and moves like continental drift, but it's very good at what it does (dishing out and taking a whole lot of damage).
If you ever feel like moving to 3D, there's a game called From the Depths that scratches a very similar itch. Fair warning though, it is not simple and after spending a long time in the designer, I gave up, because I was simply overwhelmed by all the different systems and mechanics (armor layering, gun/laser/missile/engine/autopilot construction, the actual physics etc. etc.). It's amazing to see what some players can create and the game gives you tools to build essentially anything you want.