I'm ashamed to say that I got the hard badge because of a bug I found. After 800 there was some 100% darkness ahead of me and I flew in. I apparently couldn't hit any obstacle while in it, there were no curves either and after a few seconds after leaving that darkness it appeared again ahead of me. So from like 870 to 1000 speed I didn't have to anything... (I ended the loop at 1005, by intentionally crashing into a wall.)
It's frustrating. I'm 2 points short of the max score, and I'm somehow losing those 2 points in room 5. But I just can't figure out what I'm doing wrong...
That room counts the steps you take. E.g. in the walkthrough on YouTube, the player was quite inefficient with the barrels in the top-right corner of the room (they can be moved using far fewer steps), but the rest of the room is done perfectly.
XD