Resident Evil 4 Preview Disc, known in Japan as Biohazard 4 Trial Edition, is the official trial edition for Resident Evil 4. It was released in Japan; the United States and Europe in late 2004. In Japan it could be purchased from September 2004 as part of the biohazard DOUBLE FEATURE or an extra in a copy of Famitsu. The US version was released as a gift to people who pre-ordered the game in December 2004.
The knife in this version (dubbed "Combat Knife") is a weapon inside the inventory screen, when using the knife the camera also doesn't zoom in like in the final version (or when aiming). The binoculars instead have the "knife property" where Leon can equip it at any time in this demo without going into the inventory screen. The player is able to zoom in and out just like in the final version of the game.
The English version of the trial seems to be an older version of the demo, the inventory screen is more reminiscent to past Resident Evil games' inventories where most items are placed into single boxed spaces, the Shotgun in the English demo only takes one space in the inventory screen. The Japanese version has the Attache Case and the "tetris-like" customization of it where the player can turn objects around to fit better or organize it.
Additionally, the map screen in the English trial is also remarkably different than the Japanese one, while the Japanese map resembles more the final version of the map, the English version has a map that looks like a real map on an old paper, with a compass showing "Norte, oeste, sur, este" in it, something that is not present in the Japanese version of the trial nor the final version of the game.
In the trial version there is also a "movie" option where it shows the E3 2004 trailer of the game that showcases points of the game not present on the demo version, but are in the final version. Some features shown in this trailer are different than the ones in the final release, such as:
- Leon is shown using the Broken Butterfly while in the Village, in the final version this magnum can only be acquired from Chapter 3-1 forward.
- Leon performs a different animation when stunned from an explosion nearby.
- Being able to grab Ashley from a ledge without being near the ledge / pressing a button prompt to catch her.
- Leon is shown shooting the RPG in the Temple while standing near the location Ashley is taken away, in the final release enemies do not spawn in this room.
- Luis is shown with a small beard.
- The picture of Ashley shown to the Ganado is in a different pose.
- A Chainsaw Man attacks Leon near the church.