Hey Toffi, glad to see you're making another game. I've always enjoyed your dedication to Futa games (and ones w/ barefeet, you're hitting all my favorite fetishes) so looking forward to this one!
Onto the feedback:
Controls: Feels fairly responsive, though the platforming can be a bit difficult with the running. I think the jump that required running makes sense because it forces the player to think about running but to be honest running feels a bit slugging in this type of game. Since the character model is so big it feels like their default walk speed is normally enough. The extra running feels almost unnecessary, especially around these smaller platforms. If you're going for a serious focus on platforming though I think speeding up the overall pace of the game would help, mainly dealing with her jump and fall speeds. She feels very floaty and as a result a bit hard to control.
Movement options: Can't say no to a double jump but honestly it depends on what you're going for with the level design. If you're aiming for a more enclosed setting similar to Fullfrap's "Demon Semen" then I think your current setup is fine. But if you're aiming for more open areas with pits and hazards that the player has to navigate around then you may want to consider some way to give the player more control in the air. I will say though since the character model is so big it may be a bit difficult getting platforming in enclosed areas since she'll bonk on a lot of objects.
Combos: Works fine! I don't see any issues with it. Curious to see type of combats you want the player to get into.
Struggle: I saw someone mentioning the struggling in sex scenes and I think "one tap" works depending on how you want to handle health. Often times games will have the player rapidly tap the controls to escape while they're using health and I think that works but it does make seeing the scenes a bit harder, especially if you don't have a gallery. One of the things I've seen recently in Vosmug's "Ghost Hunter Vera" is the idea of taking a static amount of damage on sex scenes but the scene ends when you tell it to. Technically it depleted a meter if you had any but it didn't affect your actual health. This allows you to view the scene without having to worry about dying in the middle of it or having to game over just to see the scene. There's a few ways you can handle it. I've also seen players getting rewarded for getting sex scenes Libra Heart's "Succubus" games or Fullfrap's "Succubus Fist".
All in all there's a lot of ways you can do it. Imo managing your health can really make or break the game. Struggling definitely works, especially in fighting game scenarios, but I don't think it works for every game. Depends on the tone of the game or what you want your player to do. I think Game Maker's Toolkit explains health the best, check him out if you're interested:
You must be registered to see the links
That's all I caught, looking forward to seeing more progress! I will definitely be keeping my eye on this thread and the blog.