I'll chime in with my 2 cents since struggle mechanics are dear to my heart and I personally can't enjoy a game without some form of them.
First, why a struggle mechanic at all?
An example for this would be that Marle game. I only played a couple minutes of it, since the scenes are based off of your MP meter and it seems like there's not much you can do as a player to keep yourself from getting raped, other than keeping your MP up and finishing fights quickly.
For me the struggle mechanics are part of what makes you immersed in the situation. It's the difference between watching a hentai and playing it, the active ingredient.
For me personally a good struggle mechanic is what makes the non-con fantasy clear, it's the difference between saying "keep your hands up" and actually tying their hands in a BDSM session. The hopelessness of the situation, and thus the sexual thrill, can be enhanced drastically by a good struggle system that gets really hard to escape, but not impossible.
But then there's the problem of clashing with the core incentive, player progression in the game. While I feel Girl in the Red Slave Collar was an excellent game in almost every regard, I still agree with the sentiment that button mashing isn't the way to handle a struggle system. The difference being that one gives you a clear turning point, where you can take player agency and escape; but fail there, and it plays the animation separately from the event. This isn't always the case in that game, but it's where I get my idea for a struggle system from, which could maybe fit a sidescroller/platformer better than the mashing we so often see.
So, how would I do it differently?
The basis for this system would be a clear
catch animation, the enemy extends their arms, or tentacles, or maybe raises their stun-gun or whatever, then, only if it connects, does it start the struggle. I'm not saying that running through an enemy should never immediately start a struggle, but it irks me that jumping over enemies in some games, your feet clip their head and suddenly you lock onto the ground and an animation plays. Maybe have the enemy play a bash animation in that case and the player takes damage, but it shouldn't start a hscene/struggle.
So next, you got caught. What now? There is a brief pause to let the player realize they got caught, maybe the screen vignette flashes pink, whatever. Now is the time for a struggle event. I have two ideas for this.
You can either base this on RNG if you want, like Unko Morimori Maru does it, where the higher chance options are more resource expensive, maybe have like an expensive "force field shock" escape, a normal "all-out fight" escape and a budget "kinda struggle" escape option...
But what I think would fit this game better would be Girl in the Red Slave Collar-style QTEs. You have like 7 chances and if you fail four, you're getting the D. The number of tries and success threshold can of course be modified by status effects, and this is just a baseline example.
Wouldn't this create a much bigger workload for the developers?
While yes, everything takes time to implement, I imagine this whole escape mechanic happening in a freeze frame, no animation whatsoever, you just see the frame where the hand/tentacle/stun-gun hit your character in the background, while the struggle UI takes the foreground. Now if you escape, you're free to go like nothing happened, and if you get caught the animation plays for a fixed time. Then, after that time, it can progress. Either an enemy that is standing close can join in, or it goes into the next phase of the animation (second tentacle up the butt?!), and this can trigger the whole "freeze frame! now escape! lost? here's your animation!" loop again.
To me this seems like the perfect system, it avoids the progression/H conflict, since the H-catch move is just a part of their moveset, and the H scene a logical consequence of failing the QTE. You can then tie it further into the overarching gameplay and lore by adding further consequences to being caught and raped - corruption or escalating bondage that's harder to escape from (lasting status effects?) into your game, but that's up to the style of game and story of course. Anyway, thanks for coming to my TED talk.
