Well, if we take only your own rules into account, they're better on anal-only. Just to remind some of these rules:
- Games on the list should have some amount of quality, not cashgrabs or shovelware.
- All the games contain anal only from beginning to end.
- All the games have female characters that are virgins and can remain as such.
- If the game has one or multiple artificial life forms, they will be considered virgin if they have no sexual experience before the main story begins.
This is how the evaluation works:
- The evaluation consist in four points for consideration
- Anal only dedicated dialogues: Characters acknowledge female character having anal sex while being a virgin.
- Anal dedicated dialogues: Characters have dialogues about the act of having anal sex during or after the encounter.
- Anal progression / corruption: The game has a system where anal sex has stats and/or is a skill that goes up
- Virginity is part of the plot: Virginity is mention during the storyline or is part of the plot.
There's nothing about the openness of the game's world. Yes, Prepare Uranus is a clumsy VN in Ren'Py format, with linear storyline and as such, should best work as a porn comic book. Karryn's Prison is a battle sex RPGM with around 10-15 GCs which are subtly modified with cum/dick/pubes/blush/smile effects, while DoL is a HTML life simulator with lo-res graphics, and cleverly looped story quests and plotlines that utimately lead nowhere. Yet, PU has more anal and anal-only dedicated dialogues than the two combined, and as for the anal progression, I don't know what's more exciting sexually for a porn gamer: studying stats and drooling over a made up number of ml of cum taken in rectum, or actually admiring the effort (amateurish and bad taste, admitedly) the dev has taken in depicting his obsession with unabashed ass-play. The variety of ass toys is impressive, some of them so original (mesh expander, bunny tail hook) that I also might consider supporting this fella ass bandit's Patreon. In both KP and DoL and loads of other games, the anal progression (or any other body part 'corruption'/expertise) are just numbers or lewd descriptions, but the visual appearance of Karryn's ass does not change much as her anal corruption progresses; the devs now seems give much more love to her boobs than booty. Feels too mechanical and soulless, if you ask me. The same with DoL, which is even more visually indifferent and emotionally cold as well, with the same dialogues repeated at nauseum: "the <insert body type> boy grabs your throat as his <insert size> penis rubs your <insert size> ass, about to penetrate. Despite inadequate lubrication, it slides in with little effort, as you push back <insert anal skill level> . He notices your chastity belt and says "So, you're a virgin? Not for long, once I'm done with you..."