That was fast! I gave it another go, so here's some more notes :D
- The tooltips showing the specifics on the upgrades screen isn't showing up after the centering
- Having the core get created on click is much better, but I think your cursor should turn into the piece, or indicate that you're in core placement mode somehow.
- The concept of a health bar is very weird here. I guess it's if you take core damage? Maybe you could have it be simplified like, lose the fight and lose a heart type of thing, and / or have your damage taken out of your scrap winnings. idk
An idea for handling cores: maybe parts could stop working if there isn't at least one core connected to them. So you could have multiple in case the ship breaks, or just one to save space and money. More just cause it feels weird to have the weapons firing when they're disconnected on their own.
There's a lot of tough design decisions ahead, but luckily it's already very satisfying to see ships blown apart, so you've got a nice base :)