Extinctathon: Polish?

I spent some time this morning fixing or improving tiny bugs, and trying to get the background music to play throughout the game (rather than being started and restarted at the beginning of every level). That caused some problems, so I'll need to come back to it later. I'm gonna have a lot of time to work on Extinctathon starting tomorrow (several hours per day), so I'd like to get the following things done this week:

• Get the music to play in the way that I want.
• Create at least five new background sprites to make the levels more visually appealing.
• Create at least five new block and enemy types which are necessary to make this more than a one level game.
  
• Make three more levels which will create one more or less cohesive World 1.
• Try adding some particle effects (pixel-y particle effects, of course) to make things more interesting.

The next month is all about content development, as I want to have something that isn't RIDICULOUSLY simple to have to turn in for Dream-Build-Play. Yeah, I know I'm not winning any prizes--that's a given--but it's really important to me to have something half decent to submit.

No video today, but I'll have something to post on Wednesday night (hopefully).