Is the 4th MC chair the last one?
Looks like it.
Okay, must say I'm liking this release a lot right now, in addition to the stage-half of 3-2, we also got an update to the "Mashu clone" enemies, they now apply the "spooky collar" effect on progression from their kissing animation to their fingering-on-the-ground animation. This new effect traps your transform option, instead forcing you into the "Slave Hack" mashu bondage suit, which is it's own status effect. This one has several tricks to it: it passively increases lust pretty much all the time you're running and fighting, and when it brings you high enough Hasumi will spontaneously start to masturbate. To make matters worse, it also "increases sexual feeling" ie increases the rate your lust bar fill during grabs. The one benefit is it majorly reduces the damage you take on orgasm. This mutated transform lasts until dispelled by purifier, it doesn't run out on empty gauge.
Both of these effects are tier 2, ie can be removed by purifier consumable only.
There is a new "enemy", more like feature scattered around stages 3-1 and 3-2, looks like 2 examples on each. These seats act as charging stations for hasumi's transform gauge, but naturally are only there to lure hasumi into their robotic hypnotic clutches. As you find and use more of them (reusing the same one doesn't change things) the seats will escalate their effects. You can reset the events and their effects through a new item in hasumi's room it seems.
The new data core bonus rooms on 3-2 are located near the right hand key card, and on a path just off the last bit of the slip-slide at the end of the stage, you need to time your jump to reach it. These 2 bring the total up to 20 I believe.
Gotta say I was not expecting the Slave Hack Suit before the 3-2 boss in the final release, so this is a real treat.
Edit: Also, Hasumi in the Slave Hack Suit + Suit Hack Visor, sandwiched between two of the female enemies getting kissed into submissions is absolutely lovely.