The author comment is really honest, I'll give you that. The game is plain simple but a bit fun nevertheless, the enemies and bullets are complicated to avoid and create interesting patters, so that part is fun. Grabbing power ups is challenging as well, you can entertain yourself just moving around trying not to die. There is not much else to talk to. The boss is invulnerable? Having no feedback on wherever the enemy is being hurt is confusing.

The game is a work in progress, adding some of those improvements mentioned on the author's comments could really bring it up.

Only 3 hours? really? not bad at all! It's fun (at the beginning) it's simple, woks. Graphics could be a little bit better on the planes, everything else could work.
Spending some more time on the game could make it even better. Maybe by making more and faster planes to appear as the game progress so it could become harder and harder till it become frenetic and nearly impossible. Otherwise it does get repetitively after a few minutes and does not challenge the player, I left the guy alone in the center and it took the planes a couple of minutes to finally kill him.