These are the missions for Level 3:
I definitely met the requirements for "phantom black". The others are a bit vague ("Outlast a nuke" means winning a battle where the enemy used a nuke at least once?), but the explicitly specified conditions for most of them were met, and none of the colors unlocked.
As for level, I was on level 2, not level 3, and was talking about the missions to unlock 3. I can see how my wording was unclear.
More broadly, I'm a bit unclear on the point of weapons carrying over between battles. You can (presumably) farm them indefinitely, but shouldn't the goal be to preserve your ships by clearing the board quickly rather than switch to individual shots to conserve ammo while the one enemy frigate left after your initial barrage chains shots and destroys both of your carriers? I wonder if a roguelike format, where conserving both ships and ammo is crucial to continuing a run, would fit more neatly.
Thanks for the extra detail, that actually clears things up!
"Phantom Black" is a much later unlock than the one you're currently working toward (it's tied to Level 5, not Level 3, there are a couple of Levels in between). The “Ship Colors” panel shows the names and hints for all the color sets, including the ones way down the road, so it's an easy mix-up to make, you're not doing anything wrong, the goal you're picturing just isn't the one that's actually "next" for you yet.
The reward you're working toward right now (to open up Level 3) is a different skin, "Storm Front”, and your Level 2 missions are the ones that lead to it.
Also, on "Outlast a Nuke”, your read on it is spot on: it means winning a Hard battle in a game where the enemy fired a Nuke at you at some point during that match.
Really appreciate you taking the time to explain, this kind of feedback is exactly what helps me figure out where the game could be clearer. I'm going to look at making the “Ship Colors” panel show more plainly which Level unlocks each set of colors, so this mix-up is easier to avoid going forward.
As for the weapon stockpiling vs. conserving ships, that's a really interesting point, and you're right that there's some tension there. I'll keep chewing on it!