I was in a hurry when I found this secret. Basically, when I decompiled the Papa Louie game, I found these unused enemies (Enemy10 and Enemy4/5), I even found some old Fort Onion background, but there were no Fort Onion codes and images found in the codes but apart from the original fort onion background as well as some "level_5" musics which were reused from the boss fight. I even found a walking Brown Onion through the game files, you can find out everything that I found over in this video:
Though, I didn't find much about it, I still able to access the Green Pepper-like (Enemy10) enemy through code-modifying, and I guess we obviously know the reason why It got removed. I'll alert you guys If I found more stuff.