I like the idea of enemies adapting--two design tweaks would help this though:

1) faster movement is better for a game like this both (controls should feel good + hard to strategize when you can't move meaningful distances)
2) the pew-pew sound effects are a bit grating, something easier for long-term listening would be better

The enemies upgrading was a nice touch. I played once on Hard/Ultra and was dispatched quickly. :)

Faster ships would make the game more enjoyable!

There are some engine upgrades there, but I agree that the initial ship speed is too low. After a couple of engine upgrades, the controls are quite a bit more enjoyable.

250, then the game started to stutter and I died. Anyways a good game. Some different Enemy-sprites, different sounds and music would have made this even better. Well done.

The feel isn't spot-on, and the idea behind the game isn't very visible. However, this is quite a solid game. Fits the theme very well.

It's kind of a sibling of my entry.

Good. It felt a bit slow in movement. Angled bullets would have been a game changer here.

Fun basic shooter.

Interesting concept with the enemies. Couldn't really see the mutations happening to my disadvantage, just seemed like the enemies were changing randomly. Faster starting movement speed would have been nice.

I like the enemies moves patterns.
The game should have been directly in Hard/ultra/turbo, there it's challenging.

would have been more interesting if the ship moved faster, otherwise great game

I got a score of 568. However, I never really saw any upgrades (I got a lazer at one point). In terms of naturel selection, If I killed the stream at the top, they would go down the bottom, and the other way round. There should really be something to stop me just flying through the middle.

I like the idea for the use of the theme, although it was hard to tell how effective it was. Was the group behaviour of ships part of their evolution? They tended to cluster in unassailable groups at the top of the screen, which meant they survived, but didn't pose much threat either. Agree with others that the controls felt a bit sluggish - the turbo version was definitely an improvement.

The enemies "adapted" to spawning at the bottom of the screen where I can't hurt them without getting hurt. Still kind of neat; just not the challenge I was looking for.

Uhm...are the fireballs evolving?...I dont get the point... played both versions...
Is this another Asteroids?

@hgcummings: yes, the group behavior was evolving too.
This clumping behavior is a byproduct of my definition of "fittest": damage to the player+bonus for surviving. If you don't stop them, they survive and get a bonus, so they end up in a mess of ships and shots, and you can't get there to kill them XD
I should have made the ships leaving the screen alive give a score penalty to the player, then you would have a better reason to avoid that (after all, you are a single ship trying to stop an invasion, gotta work hard there :-P)

Hm... Sorry, but this is just another horizontal space shooter without any innovation at all. Movement doesn't feel good and is way too slow, sfx are annoying more than anything else. It's an interesting take on the evolution theme, but doesn't work that well right now - one of the problems is that enemies just always look the same. :(

Moving seems a little to slow. But otherwise nice game!