There's only a few events that can be unlocked in the unbeatable route so basically your first fight with Porkbelly at the warehouse is good route/bad route branching path.
Win the 1st fight and then you can save before each other visit to the warehouse as every loss thereafter is a specfic bad end.
On the reverse side of this is the defeat path, you can win any subsequent 4 battle with porkbelly to get a specific bad ending - although the 4th and final battle on this route is the ouka being too powerless to even fight - the absolute defeat ending.
On good route you get a couple of hearts around the map first of all but the escalations for these only build up following the defeat route.
Defeat route events: you don't have to do these after every defeat, you can stockpile them until before the final fight.
So School Entrance: Obviously you can display the different panties to the principal to read his comments, I don't think there's a bigger purpose than this, along the defeat route you can speak to various male students (not just the entrance but in the classrooms and other areas of school) and eventually they start to harass Ouka, she will eventually start to submit to them more and more ending in the double teaming, of course you can punch them away - doing so 3 times in a row causes Ouka to face a pentalty standing outside the entrance - these also escalate.
Bullies (upper left) talk to the girl and then help her, I think you can win or lose this fight (not sure) I know if you lose the first enocunter and the second you get the garbage loss, but if you lose the first encounter and then win the second, the girl can beat them up by herself, but it unlocks a sparkle where Ouka can be attacked repeatedly.
sumo: again these escalate, on my earliest playthrough I deliberately lost to first warehoue and got ouka down to level 1 before facing the boss at level 1 I was able to regain some levels from the sumo guys at the top (sparring/fucking with the first 2 gets you 100 xp each time - no real purpose though as you are still locked into defeat)
sports: going to that guy to play football (soccer) first time, every time you talk to him after will trigget the cheearleader events.
School: the guy by the stairs is bullying the girl, you can offer to take the penance on her behalf, during the toilet event you can get a new title if you don't make it to the bathroom on time.
the 2nd class will have more thugs in it the worse defeats get if ouka goes in there she will be raped. 3rd class, you can talk to the second teacher on the right if you have done all the gym medical exam events.
Principal: visiting repeatedly gets purple haired assistant more brainwashed. Resulting in her eventually getting fucked in the toilets. (I think the toilet orgy doesn't happen on the good path, but it will still get you the bad ending)
I forgot while on the losing path, instead of the Gyaru undercover it will be another girl you have to make contact with to unlock the areas, but in the room where the Gyaru is being fucked are metal cases with videotapes in (there will be one each time you are in the warehouse) you need to give both to the guy behind the warehouse (her contact) in the hat to update what happened to her. After this she will be seen getting fucked in the area with the prankster boy, if you give yourself up to the buy guy you will end up 'rescuing' her and putting her in the medical bay.
Prankster boy: his situations escalate if you don't forgive him he'll fuck you. If you do forgive him but have done the above with the Gyaru girl, the same big guy will be wandering around and you can repeately refuse apologising to him to repeat the fucking event.
girls toilets: best to get there early if you want the first pair of panties, then go back when the boys are taking over the school for the gangbang.
I think that covers most of the more missable events.
Win the 1st fight and then you can save before each other visit to the warehouse as every loss thereafter is a specfic bad end.
On the reverse side of this is the defeat path, you can win any subsequent 4 battle with porkbelly to get a specific bad ending - although the 4th and final battle on this route is the ouka being too powerless to even fight - the absolute defeat ending.
On good route you get a couple of hearts around the map first of all but the escalations for these only build up following the defeat route.
Defeat route events: you don't have to do these after every defeat, you can stockpile them until before the final fight.
So School Entrance: Obviously you can display the different panties to the principal to read his comments, I don't think there's a bigger purpose than this, along the defeat route you can speak to various male students (not just the entrance but in the classrooms and other areas of school) and eventually they start to harass Ouka, she will eventually start to submit to them more and more ending in the double teaming, of course you can punch them away - doing so 3 times in a row causes Ouka to face a pentalty standing outside the entrance - these also escalate.
Bullies (upper left) talk to the girl and then help her, I think you can win or lose this fight (not sure) I know if you lose the first enocunter and the second you get the garbage loss, but if you lose the first encounter and then win the second, the girl can beat them up by herself, but it unlocks a sparkle where Ouka can be attacked repeatedly.
sumo: again these escalate, on my earliest playthrough I deliberately lost to first warehoue and got ouka down to level 1 before facing the boss at level 1 I was able to regain some levels from the sumo guys at the top (sparring/fucking with the first 2 gets you 100 xp each time - no real purpose though as you are still locked into defeat)
sports: going to that guy to play football (soccer) first time, every time you talk to him after will trigget the cheearleader events.
School: the guy by the stairs is bullying the girl, you can offer to take the penance on her behalf, during the toilet event you can get a new title if you don't make it to the bathroom on time.
the 2nd class will have more thugs in it the worse defeats get if ouka goes in there she will be raped. 3rd class, you can talk to the second teacher on the right if you have done all the gym medical exam events.
Principal: visiting repeatedly gets purple haired assistant more brainwashed. Resulting in her eventually getting fucked in the toilets. (I think the toilet orgy doesn't happen on the good path, but it will still get you the bad ending)
I forgot while on the losing path, instead of the Gyaru undercover it will be another girl you have to make contact with to unlock the areas, but in the room where the Gyaru is being fucked are metal cases with videotapes in (there will be one each time you are in the warehouse) you need to give both to the guy behind the warehouse (her contact) in the hat to update what happened to her. After this she will be seen getting fucked in the area with the prankster boy, if you give yourself up to the buy guy you will end up 'rescuing' her and putting her in the medical bay.
Prankster boy: his situations escalate if you don't forgive him he'll fuck you. If you do forgive him but have done the above with the Gyaru girl, the same big guy will be wandering around and you can repeately refuse apologising to him to repeat the fucking event.
girls toilets: best to get there early if you want the first pair of panties, then go back when the boys are taking over the school for the gangbang.
I think that covers most of the more missable events.
