lol i asked about this over a year ago and got no response, i can't imagine it's not a deliberate choice at this point because pretty much every other renpy game i've ever played has more slots.
So yeah this one seemingly the same as the other game (swing & miss) has inconsistencies in that the futa D will turn huge in some scenes and tiny in others, also the husbands D also is shown to be small in some and quite big in others. So again the whole the futa's D is so much bigger so she easily turns the wife into her sex slave cause the husbands D is so small just becomes weird. It would be nice if in a future game it was consistent in the sizes. Like how in one scene where the futa + husband fucks the wife the size is clearly different with the futa being seemingly twice the size. But when they get boobjobs / blowjobs for instance they will have the same size and seemingly the same D almost, which is probably a sign of them just reusing content. Which is fine to some degree but it just becomes weird when the whole premise of the NTR and plot is the size difference and then their shown to be the same size....
Also I just gotta say my piece about the exhibition ending cause that one was just wow.
There are also quite a few endings in this one most of them are "bad" endings in that the futa doesn't manage to make the wife her sex slave.
Most of the bad endings are the futa messing up in some way or not managing to make the wife hers, but there is also a bad end where the futa turns into the wifes sex slave.
Thats probably the easiest path/ending in the game to get since the default path is seemingly the pregnanacy path. Since all it requires is for you to have sex with the wife pretty much. Then you can just pick the pregnanacy ending once you get the option to pick an ending.
So on a side note the pregnancy tag should probably be added to this game