Yes, once the space ship status meter reaches 100% (the green bar at the bottom of the screen), you beat the game. If the player died, the meter reset back to 0%. Actually, I was thinking about adding a checkpoint every, say, 20 or 30%. But in the end, I changed my mind. Also, there is only one ending scene!

Ah! I should've put a bit more animations in the intro scene to indicate that you're not the mother ship.

For the random death, hmm... I wonder why that happened since I haven't encountered them myself yet. But I kind of suspect that maybe the player is on the edge of the screen and got stealth attacked by the enemies outside of the border. Or perhaps multiple enemies are stacking on top of/under the player makes it harder to see, and when you move, they trigger tons of damage immediately.