The remaining percent eludes me!

So yeah, finished the game, 99% complete. I have all of the weapons, all of the ship upgrades and all of the stars. I've also defeated all of the bosses.

What could account for the remaining percent?

Ooo, never mind. I didn't realise the missiles went to 25, I thought 20 was max. Found the upgrade. Woo!

Hehe. I don't blame you, a lot of people think that at first. Actually, when I was at the 3rd boss thought there were only 10

Yeah! I don't actually remember getting the upgrade to 20, so I was thinking maybe I'd found a glitch or something, but no, it's all good.