Weight gain will require you to redraw all 772 for it to work so your going to need a team of artist willing to work on this project. If you want a pokemon styled game with your choice of expansion in it then the two above games are ideal as the target sprites are already human like, but this idea was easy for breast expansion as all my team really needed to do was add boobs of gradually increasing size to the existing sprites. Indeed, it can be done as someone/group has done this with those pokemon games to make the Moemon, and Touhoumon games and many more.

So good luck with this and succeed where my group failed Also decide what fetish your going for and how each moemon changes to keep things constant, if your going solo your fine but a group you’ll need to plan this and divide up the work as you’ll be working on 772 sprites if this is Moemon Emerald ver This might be a wordy reply but just take this, if you want to change the Moemon sprites themselves it’ll be a lot of work, so make sure you really want this and take your time on it or can find a good size group to help work on this. Our group’s main member made a a pokemon ruby hack with all the female trainers were given huge breast that gave us this idea, and I’ve been wanting to try that idea but with Moemon instead, but only for the trainers. the other issue was also getting the new sprites to actually work, even using the same pallet of colors we found there were problems with some now displaying correctly and base on the tool we used we could find that the sprite end up being too big for the rom or the tool we used could only pull out negative colors The issue was with so many touhoumon sprites and there was less then the original 151 pokemon that we couldn’t keep going as we all lost interest due to personal lives.

I was part of a group that tried something like that more for BE, WG and a few other fetishs years ago with a Touhoumon firered ver but it proved to be too much for us and the project died.

Moemon platinum back sprite fix