@C.J. Cuypers
Hi there, was not planning to re-reply here, however after reading above. Your Game idea is fine, and will work.
With out pre planning on design, this seems to be a combination of user and engine fault.
There is nothing wrong with using fpsc models, lower poly is a good choice in a 32bit environment, used for many years.
However did you update all fpe's for this media to be used? Double checking texture formats and script directories?
Your level sizes are large in data from Texture data stacking in memory, as soon as you hit save, this stored data will save to your fpm.
Please feel free to DM and I can educate you further on how to have this running, with no changes to the projects looks at its current stage. Can not guarantee you will get the 20 levels before hitting the next ggc memory cap, though if your invested worth a try right. Yes this will need to be rebuilt, as I mentioned in my first post, texture data stacking is irreversible.
Also yes 512 suggestion from the user above is a good option if wanting to squeeze out some more room, though I do not believe texture size is the problem here.
Also if your not comfortable with DM, let me know and I can arrange a run down here of pre planning/setup using ggc. All the best
@synchromesh, I've noticed some of your replys over the years (inc steam), where I believe you try to assist where possible, great. I suggest using that time to do some research on ggc workings and faults and help educate users, especially on engine faults and memory limitations, Its an interesting topic and I would hope, someone like yourself to be an advocate for.