Alien Hominid HD

you probably got 1040 points not kills the i got the achievement on the first levels second boss. what you do is you wait until that boss with the eye beam or something wait until he is able to fly in the air and then an infinite number of fbi or whatever should come through just keep turning left and right, shooting. Remember to jump when he crashes down it's incredibly easy this way.

Just keep playing. If you play long enough in one go, you're bound to get 1000 kills. And if you want to make it even easier, you can put the game on easy so you don't have to worry about getting a game over.

Im sure 1040 was just your point total. To be sure you get all 1000 kills and keep track just stay in the very first area of the very first stage and spam the infinite respawn like you said. As long as you dont blow up the first building or anything else causing your point total to go up you can use it as a reliable counter source.