See,
this guy gets it.
Thank you.
The issue, I think, is that Zero and I apparently have very different ideas of what a "Yuri Mod" actually is, or ought to be. To
me, a "mod" implies a lot more than just swapping some images and doing a search-and-replace on the text to change "Sonic" to "Amy" — I mean, sure,
technically I guess that counts as a "modification", but the result is hardly what
I would call a functional game. Changing the babysitter from a boy (Sonic) to a girl (Amy or Sally), and having the result be something that makes
sense, requires a
lot of rewriting of the actual dialogue and scene descriptions —
and, yes, a certain amount of code changes, because there are places in some of the hentai scenes where "you" are given the option to put on a condom (or not), or given the choice to cum
inside Cream or cum
on her, and neither of those choices would make any sense when it's two girls going at it rather than a girl and a guy. (And those are just the two most obvious examples I could think of off the top of my head; there's plenty of others.)
Even the very first menu in the game, when Cream says "Mommy says you're going to watch me", contains a response that would make no sense with Amy as the babysitter. You pick the choice "Yeah, I hope that's okay with you," and Cream replies "It's kind of weird having a boy for a babysitter, but..." You can't just change the word "boy" to "girl" here, because why would it be weird for Cream to have a girl as a babysitter? So, now you have to either rewrite this dialogue to something else, or (code change!) remove that option when Amy is the sitter, and not Sonic.
This is where all of the difficult work is.
Now yeah, sure, if you don't
care whether the dialogue and descriptions match up with the images you swapped in, or even make any sense in the context of Cream+Amy rather than Cream+Sonic... then yeah, sure,
that's a mod you can probably slap together in a couple of days, especially if you raid a few image archives like rule34 or e621 for the art. But if you don't actually care about the dialogue and descriptions... why
bother with the game at all? What's the
point of making a "Cream-plus-Amy Yuri Mod", then? Just to see some naughty Amy+Cream images? You may as well just go straight to one of those online image archives to get your fix, and not even
bother with the game, then.