Thanks very much! Also haha, you're right about the line effect - it was all of those things. The player ship blowing up, but also being obscured by the lines which were meant to represent the 'cloning' process, which repairs the player and also creates a duplicate of themselves to fight alongside them, aaaand the player is also invulnerable during that effect, so it's kind of a shield too :P
The turrets are not indestructible, they just have high HP to keep the game going a bit longer and I ran out of time to add hit feedback effects so, my bad. Thanks again!