This is a ton of fun! Wow!
You're really making the simplistic art style work for you. The combat's fun, you have UI elements which help the player out a lot in learning game mechanics, and there's a lot of polish in here already.
Add in some music, some atmosphere, and give my cards hotkeys so I don't have to click each one of them, make player turns automatically end if they have no cards or have no energy and no 0-energy cards, and you'll be well on your way to success. As-is, this game is already ready to be public alpha'd and I'm certain that with the right marketing you'll definitely find not just an audience for this title but an enthusiastic one.
I've yet to finish a campaign yet - but if you can keep the game fresh by adding in Challenges (specific ships with specific decks in more linear campaigns, making it a bit more of a puzzle game) and unlockables (cards which are added to the 'deck of possible cards' when you meet certain conditions) this game I could see easily being worth $20-30 when it's all done and finished.
I'm very excited for you and this project and I hope you gain some measure of fame and reward when this game's done and out.