Hey. I'll drop here some things that could work. I suppose they are all super time consuming, so I would only recommend the first two ones as short term suggestions:
-Make it possible to skip dialogues in an easier way (clicking anywere, or holding ctrl to skip quickly). I know you have worked really hard in writing the dialogues, but after you have read them 2-3 times, the magic of novelty unfortunately goes down.
-Randomness in waves: after some days playing, the game becomes predictable. Adding a point of random should fix this.
-Introduce more game mechanics, for example: a debuff that makes you run in the opposite direction that you are pressing, mediated by lust; another example could be becoming overattached to certain evil waifus (developing a fetish for them?), which could lead to becoming more vulnerable to them; related to the previous, it could be interesting to be able to "heal" from the different fetishes if you avoid them for long enough, so that the game punishes the player for playing badly
-More game over scenarios: I really liked the Kalysea and Lily game overs! And not only because they were hot, but because it adds pressure to the game knowing that you can lose by getting caught a bunch of times. I think all evil waifus should have 1-2 different game overs, in due time. Also, this could combo well with the previous point about personal fetishes and healing from them (maybe the player wants to force the game over, or maybe you want to avoid it).
-Upgraded evil waifus: maybe once in a while, a super Morgana or a super Maeve could spawn! One particularly mean that has a ton of HP and is harder to avoid.
-More content: this is super obvious and probably require a ton of work, but more items, more evil waifus, more Luna quests, more fetishes, more bosses...
I dumped here all that came to my mind right now, obviously there is no rush. I really like the project, keep up with the good work :) .