YK: Before answering, let me first define more accurately the context for which you use of the word 'version'. Usually, in the development of cinematic games, a game system is integrated into a world view & stories which are already defined, but this was not the case for biohazard 4.
Our priority was to build a 'game system & situation that induced fright & horror' first. Therefore, both the Hallucination and the Castle were essentially trial & error ideas that we thought of implementing which ultimately didn't appear in the final version, of course.
In terms of the order in which things progressed, the Castle scenario came first it was the most established - then the Hallucination element came second.
However, when the Hallucination was introduced into the narrative, the concept of the Castle, where Leon kept fighting while an illness was destroying him, was passed on. So although the Castle was replaced with the Hallucination, it remained in the game as an expression of Leons illness.
Also the mechanic where Leon could view a hallucinatory or spirit world and fight against its residents when the fog filled in the room, was considered then too. We had so many trials and errors in the development.
Shibata the director had a very clear concept which he described as seeking the horror. He had the image of 'the horror of mogaki' or struggling. It can be difficult to directly translate this 'mogaki' word into its exact meaning, but it is a situation in which you try to wriggle with your whole body in fear, but cannot escape. He seemed to want me to create not just physical mogaki, but rather a state where Leon couldn't resist mental or psychological pains & difficulties. A kind of mogaki thats similtaneously mental & physical.
This 'mogaki' was used as the key concept within the production team frequently as the keyword created by Shibata. In fact, the word mogaki is sometimes displayed during the continuous pressing of buttons to escape from the enemies in actual biohazard 4 game. Unfortunately, it's not in the non-Japanese version, as the word doesn't translate directly into other languages.
Shinji Mikami, the producer, also stated Biohazard was a horror game, and often demanded a production that was revolutionary in the horror genre - the concept he used was that of 'full model change', right from the beginning of the biohazard 4 production. Mikami first wanted something like The Thing, where you could not tell who was the enemy and who was a friend. I suggested a system where the game was about 'fears & doubts', but recapturing that essence in a game structure proved very difficult, so it fell through.
With such trial & error I had some world views & concepts of game systems to test, and I thought they would be suitable to express the 'horror' that Shibata, our director was searching for. The idea of hallucination to be able to see into another plane of reality, was one of them.
In the winter of 2002, I gathered the staff and showed a scene from a film. It was a scene from Lost Souls, by Janusz Kaminski where the room started corroding blue and a killer started emerging, while the main character was washing her hands at the sink. This scene, this hallucinatory vision from the character, and the way the room changed in real-time moved me very much emotionally. So I brought up the idea of attempting this in a game.
First, I suggested that the main character travelled into a hallucinatory world which was caused by something caught in his vision, a trigger of horror. The first thing I wanted to create was the structure that the world would transform into - a horror hallucination world in real-time when viewing pictures, and other points of interest, or letters, etc. These would become triggers, as a means of seeing the story with clarity understanding the truth behind the scenario, or seeing another truth outside the real world scenario.
It was very interesting but was extremely difficult, as it meant effectively having two different worlds in one, operating simultaneously in real-time, which was a challenge given the memory restrictions & hardware specs in those days. In the process of resolving those problems, ideas from the other staff were adopted and the black fog, Leons monstrous arm, and the Hookman appeared in improvements & experiments.
There were many experiments & proposals, such as peeling skins off an enemy when attacking for example.
