Because the progression comes from capturing the monster girls. Honestly surprised you wouldn't know that.
Honestly the november build is a disappointment and it is a real shame. Zell had great game design decisions with both FoBS and Succubus but now with this remake we have lag issues, lack of optimisation but also bad game feel. The dash is extremely klanky to use due to stopping at the end, teleporters don't work, ladder doesn't work, and the entire system of weapons and skills make the game extremely alpha to even pre-alpha rather than a demo or beta build. It is a downgrade in every aspect.
It is extremely disappointing. Zell would need to adjust a lot of things to make this a passable build compared to the previous stable versions.
Keep in mind these are being made every single month. Tangible things get added every single month. While optimization would be great and adding new features that are being teased, this is effectively a new game in a new engine with naught but a set of guidelines on what the game should turn out like relatively. Progress is going to be slow, reoptimization is going to be needed constantly, things are going to be added and removed consistently so newer builds can show some form of progress even without perfectly solid coding. So while your disappointment is understandable, you have to think of this from a dev's perspective rather than a player's. While they want to show progress, that progress can't be perfect every time. They cannot always show everything they want to all at once because they haven't gotten all the ducks in the right row yet. So it's better to focus on what's being added and the potential of that rather than the flat value of what's there and how it stacks up to something else.
Also, for the record, FOBS (the first version) and Succubus Affection are completed or at least relatively fulfilled games. Comparing this, an unfinished project that still has a lot of kinks, to two games that had a lot of time to be developed and ironed out is not really fair in the grand scheme of things. It's likely that this remake will eventually reach the level those games could and live up to their names, but you can't expect that out of something that's still very early in its development cycle, especially not when they're having to rebuild greatness rather than just flat out make it. (The former is harder because a standard was already set, while the latter can make its own standard. Both are difficult of course, but people will automatically be harsher towards a remake than a new game.)