Fun little game! A warning for anyone with high refresh rates, though: the things that teleport the astronaut to the alien mess up at high refresh rates. You may need to set your machine to 60hz.
The teleport itself works fine, but then if you try to hit the little alien while he's still in the little glowing circle that activates the teleporter nothing happens. He just makes his little noise and stays there, but there's no way to get him out of the circle. My setup has a refresh rate of 360Hz, which has caused problems with several other games before, so setting that to 60Hz was the first thing I tried to fix it and it worked. Not sure why it's just that function it doesn't like, though.