Current progress
@alanxoc3 was hard at work on the game last night, and here's what it looks like now:

As well as the obvious stuff - a new alien enemy and clouds in the background - there's some subtle details like the bird drifting around the play area instead of staying in one place, forcing you to call it back to you. He's also added in the music, and a few new sound effects.
Day 2 is here, so time to crack on!