I'm slowly progressing with the alien waves for the demo level and I think it's going okay. If I play without wanting to power up, you can more or less run through without getting hit (so far). But if I get greedy and want all the coins, then it starts to get tricky; which is the idea.
I've mapped out about one third of the level, although I've extended the start a little to make the introduction a little simpler - mainly so theres no backgrounds while you get used to moving around.
I also fixed the 2nd bug in my list from yesterday, where the collision radius wasn't being used.
So.... the demo is progressing slowly. Slow but steady! which is of course better than it has been; stopped and dead.