a good start
I get what you're going for, but you might want to try a few things to get this off the ground. A few things I noticed;
-The "bullets" you fire do not destroy the nightmares, they just push them back. This would be a great idea if the number of baddies were fewer, or there was some form of power up or auto-fire to help you push them back (maybe there are, this would be an example of how far I was able to get in the 5 tries I gave it)
-The spawns for baddies come completely random, and I was having issues right off the bat when 6+ nightmares spwaned right next to the bed. Makes it real hard to stop them when you can only push one back at a time, and they are pretty much ontop of your goal.
-The dream catcher is tiny and in a very difficult spot to push your baddies to. If you're getting swamped on the left side on top, you have to go above them and shoot down and out, which leaves your right side completely open.
This could all be fixed buy adding splash push back to the bullets, limiting the location of the spawns or number of spawns, adding more push back and stun to the bullets, or making the nightmares die from bullets over time, or even adding more dream catchers to allow destruction of the nightmares from more than one side.
Anyways, it's a nice start, and I'll anticipate looking at this once a little more polish has been applied.