There's a lot to commend here. I like the traveling wave of death. It really fits the theme. And the graphics, at least in terms of what's here, are are good. The music is fine and the controls are tight, perhaps the most important part of all. I also really appreciate that you introduced the controls as they are needed and in game rather than interrupting us, or front loading them all at the very beginning and overwhelming us.
One thing that would have strengthened this significantly is more variety in the graphics however. Because it's an Runner there's extended periods where not much is happening other than holding right and more gfx variety either in the foreground or background would have been nice. I think that from a gameplay perspective there's a little bit of the same issue: not quite enough variety. Here you definitely do introduce new mechanics of each level so I don't want to overstate my point. But I still felt like there could have been a little bit more going on. For instance it's nice that you don't actually have to run all the time but I didn't feel like that got used very much in the level design that I saw (I stopped around 5?). To be honest I'm not a huge fan of Runners so my advice here may well be poorly placed. However what I saw I enjoyed which is better than what I can say for a lot of Runners.