I 100% agree with your choice to don't turn the ship because now i understand that it's a top down game and you always want to face the enemy in front of you, but i still suggest you to try at least to tilt it like 10°/5° to face the direction where you are moving while going left or right and then smooth the rotation back to the original direction when not pressing the left or right inputs, Try it just to see if this feature fits well the game or not. Over all It's a nice game idea, I'll take a look at it every now and then.