I am over the moon right now. Until today, I'd thought my mons were lost forever. Never did I think there was a fix as simple as this. My utmost thanks to everyone who offered assistance.

Apparently, only my first save slot was corrupted. This resulted in any save named "Game_1" crashing my game. Following the pinned post and redownloading Allgen hadn't worked at all, and I was at my wit's end. I resigned myself to restart till this morning, when a kind soul offered their Allgen save to me. The first reload attempt worked like any other-- crashed game, error noted in errorlog. Then a weird idea hit me- "what if I renamed the file to Game_3 instead?" So I tried... AND IT WORKED.

My brain was grasping at straws come this point. "Would this work on my save, then?" After renaming the file to Game_4, I couldn't believe my eyes.

There was my file, in the exact state that I left it in. Mons and all. Now the adventure can finally continue, all thanks to your help.

Happy gaming! Keep backups of your backups guys~