The developer trimmed a lot of the existing gameplay away in order to focus more on the battle grid and wave timed elements. Honestly, the previous iterations only triggered attack waves when you became a 'threat' which gave you some time to build up your forces. This version is RNG out of the gate since you start with 1 orc, 1 orc baby, 2 goblins, and 3 human prisoners with RNG bonuses. If you've rolled low on starting stats you're better off restarting because wave 1 is 5 enemies any they'll chew through most defenders like a hot knife through butter for an instant game over.
I hope they bring back the map and strategic elements back for other ways to recruit and reroll monsters/girls.
Also, its very subtle, but each character has a range for their base stats beyond their bonus. I've had elves with max health of 20 +3, elves with max health of 30-2, human soldiers with 15+5, and human soldiers with 25+2. It might be because I was breeding them with the player character, but it gets hard to keep track of where they pop in from over time.
I think the only characters in game so far are: Goblin, Goblina, Orc, Oni, Human, Elf, Sister, and Magic Swordsman.
However, there doesn't seem to be any hybrid of combos beyond the sister as they've trimmed back a lot for the new systems.