Same here, although I don't know if it's a bug, or something I did wrong.

You need to hold space through the entire first BOSS, not the first level.
I managed to get it, so I don't think it's bugged.

I did it through the whole level inc. the boss, b/c I wasn't sure when the game counted the boss as having started (when you first saw it, or when you walked into that area, or when it became damageable, or when the logo appeared...) When did you start dancing?

Originally posted by Arakus:

I did it through the whole level inc. the boss, b/c I wasn't sure when the game counted the boss as having started (when you first saw it, or when you walked into that area, or when it became damageable, or when the logo appeared...) When did you start dancing?

I started dancing as soon as I realised it was the boss stage, before moving into the arena.

I started dancing before coming out of the start portal of the boss stage, held space and didn't die once to the boss, defeated him, entered the end portal and didn't get the achievement. I think it's broken...

Originally posted by Linkblade:

I started dancing before coming out of the start portal of the boss stage, held space and didn't die once to the boss, defeated him, entered the end portal and didn't get the achievement. I think it's broken...

I just got it too. It's a bit unintuitive. I think essential is to start dancing before entering the boss stage, that is before coming out of the start portal, during the loading screen, better before entering the end portal of the russian guy level.