While the style of the game is fine and the game itself runs smoothly, I have to say that the level of difficulty curve is WAY to steep at the start. The enemies took too long to kill before they built up in sufficient numbers to make dodging almost impossible. It took me several tries just to get enough points to boost my energy so I wasn't sniped out of the sky under 5 seconds.

Once I finally got past that first stage, it felt like I was starting all over on the next level. There are also two blind spots: 1) the enemy-spawning shed on the level, under which they can hide and you can't hit them and 2) the opposite wall due to robobird's wingspan (enemies are small enough to hide in it). My recommendation for this is to add some sort of dodge mechanism to make avoiding enemy fire easier (robobird is too large) and to address the difficulty scale.

Otherwise, nice job.

not bad, a bit too difficult in the beginning, and a bit too easy in the end, but pretty good.

didn't find it all that fun it was just a lot of dodging

I like the idea, but it takes so many shots to kill one alien while they kill you in only a couple even with it fully upgraded. Fix this and I'll give you a better score.

Is this game a work in progress? Cause in case it is, this review will not be justified...

But since you uploaded it on here, the faults:
No proper instructions; You only know how you control the bird (and even that you only know from reading author comment) and that you're supposed to destroy enemy bases.
Hard and broken like you didn't even play the game; The mobs that spawn stay there even after you die - so if i'm trying to destroy their spawner (which is pretty impossible on its own) the cannons will overflow me on my next try.

It's an average looking game with a low grade design and as such doesn't deserve more than 1.5 stars IMO