In general, it's a fine game with good ideas and nice graphics, but too unforgiving. You make one mistake and despite having three hearts left, you go back to start.
I don't need more levels, because I can barely make it past the first red plane. And when I die, replaying it all over again for a little mistake is annoying and eventually, I stop being interested in playing.
There's no temporary invincibility, so crashing into a building, the top or bottom of the screen is an instant game over. You lose a heart if you crash into an enemy because they are destroyed, but the enemy immediately after them causes you to lose another. The green planes take too many shots to kill and because you only shoot in front of you, unless you destroy them immediately after they appear, they'll crash into you from below or above. You can't move left or right to allow you to circle around them, so once they get close to you, you're essentially screwed.
You could make all this a bit easier by making your weapons more powerful, or extending the time intervals between enemy encounters, *fixing* the temporary invincibility, decreasing the speed, or the health of the enemies… pick anything.
I wouldn't mind losing the auto-shoot feature in exchange for more powerful bullets, even with larger intervals in between.
The red plane moving with you is a nice idea, but unless you make sure to kill it as soon as possible, it's going to kill you when the buildings appear again, together with regular enemies. I'd loop that section of the level (even with buildings) and spawn regular enemies only after you defeat the plane, otherwise, it can be almost impossible to win afterwards.
That's it.
I originally didn't want to write anything, since I couldn't see very much of the game and really didn't want to replay the initial sequence for 150th time, but on the other hand, the game isn't bad or anything, just annoyingly difficult.
Seeing you don't have any comments from other people, perhaps some of them shared my sentiment.