The less-remembered 2MB remix MAX. (period), available only on the Japanese console version of Extreme. It was the utter peak of difficulty escalation in DDR before In The Groove's challenge-oriented design forced Konami to up the ante to match. The fourth wall gets a beating - the background video depicts recording sessions and the distorted voice is whispering "WHY DO YOU NEED KONAMI ORIGINAL SONGS?". The normally silent slowdown has a tiny glimpse of nostalgia to the first ever DDR mix, with the faint background music and step patterns taken from PARANOiA, the first boss song of the series. After a few seconds of standard MAX fare, the speed rockets to a staggering six hundred beats per minute, the fastest official song scrolling speed around that time. The rest of the MAX songs skirted the line between "legitimate song" and "difficulty justification", but MAX. is an unabashed attack towards the player.
It's on the fence whether or not it's technically a "MAX" song, but MAXIMIZER is just a minute and a half of fast, pulse-pounding, hardcore techno goodness.
PARANOiA HADES from Dance Dance Revolution SuperNOVA 2. Think of it this way - one of the hardest songs in the game. Halfway in, the song drops in speed, then speeds up slightly again. Partway through that speed up (at 1:26 in the video), the build-up begins. Every time without fail, this part makes the hairs on the back of my neck stand on end, as if to say "This next part is going to kick your ass." Add to that the disturbing backing video, and you actually fear the next part of the song, in the most awesome way.
Hana Ranman -Flowers- by TĖЯRA from DDR SuperNOVA. It also later appeared in Beatmania IIDX 15: DJ TROOPERS.