There have been many releases and rereleases of the original Final Fantasy on various systems; one of the least-known ones is Final Fantasy for the MSX personal computer (specifically, the MSX2). It was released after the original Famicom release, but before the US NES release of the game; as a result, it's closer to that original version of the game than the later releases that took the NES release as their basis (so it has the original Beholder sprites instead of Eyes, the topless Medusas, the neat-haired Master sprite, etc.), but it has several advancements of its own that set it apart from the original Famicom release.

As for what those advancements are that set it apart, the MSX (and especially the MSX2) had more powerful visual and audio capabilities than the Famicom/NES; as a result, the MSX release had more and more varied colors in many of its sprites and higher-quality chiptune music. On the downside, as a computer in the 1980s, it was distributed on a 5 1/4" floppy disk (and required another to save), which means long loading times for...just about anything. In addition, as as a multipurpose computer, the MSX was considerably less optimized than the Famicom/NES. As a result, in addition to the loading times, FF for the MSX is considerably slower than the original. There are also other minor differences, such as the random encounter grid being slightly different than the original and a far more wildly inconsistent encounter rate.

This mod attempts to visually turn the Pixel Remaster into something as close to the MSX release as I can get. Right now it only includes party and enemy battle sprites, battle backgrounds, map sprites for party and NPCs, and replacement of the world map tileset. (Note that that last is incomplete: I'm not sure how best to handle the transparency in the "earth rotting" animation from the prologue, and obviously the map is different from the actual NES/MSX version, so I've done my best to MSX-ize the PR map. I may yet do a little more with the transition from desert to grass and with the brown edges of landmasses.) I've also included some UI options to mimic the MSX version's interface. Eventually I hope to expand it to include equipment sprites (including new MSX-style shield sprite) and replacement of the various town and dungeon map tilesets into something much closer to the MSX style.

This mod is highly indebted to Axel Voss's FFI Pixel DEmaster, which does the same thing this is trying to do but with the NES version of the game; several elements (most notably the general structure of the battle background setup and several of the new battle sprites that weren't in the original) are patterned off of his mod.

This mod also makes no gameplay changes to return the game to its original NES/MSX difficulty, because a mod already exists for that: Origins Normal Mode Rebalancing, which returns various parts of the game back to the versions used in the NES/WonderSwan Color/PlayStation "normal mode" versions. This includes enemy HP, formations, experience, and gold; party experience needed to level up; removes the remake-added items from shops and restores treasure chests to their original rewards; and much more. To ensure enemy formations show as intended, you will probably also want to use the optional addition to that mod, for compatibility with the Pixel DEmaster, that restores enemies to their NES placement. While this isn't entirely accurate to the MSX release - it's using the NES encounter grid/rate rather than the MSX's - it's definitely closer than the vanilla PR gameplay.

As the MSX version never had an official US release, there's also no "official" English text for it, so you have several options for how to handle it that are all of equal accuracy, in addition to the vanilla version. A fan translation of the MSX version was released several years ago using the original NES translation, and some support to mimic that version exists with my NES Text mod, which changes most of the text of the game to reflect the NES version (and thus, the MSX fan translation). The aforementioned Origins Normal Mode Rebalancing mod includes by default game text changes to do the same with the PSX Origins names and usage of various things, so if you choose to use that mod, you can either keep that part in or remove it (the mod page gives you instructions on removing it if you wish). And finally, I have two other mods that edit the text: my Consistent Terminology for FFI revises the vanilla PR translation of this game (as it does with all the other FFPR releases) to be consistent with each other in their use of shared terms, and my DND Terminology for FFI mod revises the vanilla PR translation of the game to reflect the very direct basing of the game on early Dungeons & Dragons.

Installation instructions:
This mod has several modular elements, which can be mixed and matched. Some require Magicite.

• Battle Backgrounds - Unfortunately, neither Magicite nor Memoria can change battle backgrounds at the moment, so this has to be done as a .bundle file release. Extract the files within the folder to your StreamingAssets/aa/StandaloneWindows64 directory, and choose to replace all files. (As this makes permanent file changes, as opposed to the temporary and easily-reversible ones of Magicite and Memoria, you may want to back up the vanilla battle background files first, to avoid having to verify and redownload files under Steam.)
• Battle Sprites, MSX Outlines (requires Magicite) - Extract the directory into your Magicite directory (which is usually StreamingAssets/Magicite, unless you've changed the default; if you've already installed Magicite and the Magicite directory doesn't yet exist, you can just create it). This will replace all party battle sprites with their MSX counterparts, or in the case of sprites that didn't exist in the MSX version such as the ready or spell-preparing sprites, original sprites that are in the style of the MSX versions. This version gives party battle sprites outlines matching the black background, as the original MSX version did (well, technically it just had no black outlines whatsoever for them and used the black background and transparent pixels to get the same effect, but we're not working with 8-bit limitations and have no need to use that specific hack). Keep in mind that this means that by default, any effects that change outlines based on their color - most notably status effects such as Protect or Haste - will not work, and party members under Invis will be truly invisible rather than the outline-only effect that the vanilla PR gives.
• Battle Sprites, PR Outlines (requires Magicite) - The exact same as above, with the same directions to install, except that the outlines for this set of battle sprites are in the same color as the Pixel Remaster vanilla versions. This means all outline effects such as Protect, Haste, and Invis will work as intended. However, the outlines may show up faintly against the black battle backgrounds, as they are a slightly paler black.
• Enemy Sprites (requires Magicite) - Extract the directory into your Magicite directory (which is usually StreamingAssets/Magicite, unless you've changed the default; if you've already installed Magicite and the Magicite directory doesn't yet exist, you can just create it). This will replace all enemy sprites with their MSX counterparts, including the bestiary thumbnails that show when you look at a dungeon in the bestiary map.
• Map Sprites (requires Magicite) - Extract everything within the folder into your Magicite directory (which is usually StreamingAssets/Magicite, unless you've changed the default). This will replace all party and NPC map sprites with their MSX counterparts (or MSX-ized, in the case of characters whose new sprites are too different from their old ones like Bahamut, or characters who didn't exist on MSX like Cornelia's chancellor), as well as all vehicle sprites and some map object sprites like the Levistone and Adamantite.
• Overworld Map (requires Magicite) - Extract everything within the folder into your Magicite directory (which is usually StreamingAssets/Magicite, unless you've changed the default). This will replace the tiles on the overworld map with their MSX (or MSX-ized, as before) counterparts. I'm not 100% happy with everything on this, so there may still be some changes made, but at least it's complete enough for an initial release.
• UI Windows - This will change windows throughout the game to match one of the MSX versions.
  

For UI Windows, there are three versions:

• "Slate Blue and Light Gold" is the window theme matching the MSX menu and gameplay windows;
• "Bright Blue and Gold" is the window theme matching the MSX dialogue windows;
• "Black and Light Gold" is the window theme matching the MSX battle menu windows.
  

Unfortunately, no support currently exists for being able to have all of these coexist in the correct places, so you will have to choose one of the three to use throughout.

As neither Magicite nor Memoria currently has support to change UI windows, each window type currently has support for two ways of changing them: there is a .bundle file that can be extracted to your StreamingAssets/aa/StandaloneWindows64 directory (which makes a permanent file change), or a .png file that can be used with Silvris's FFPR ColoredWindows tool. If you use ColoredWindows, follow the instructions it gives, and replace ColoredWindows' default UI_Common-WindowFrame01.png with the one of your chosen window. (If you do use the ColoredWindows mod, remember to set the tint for WindowFrame01 to 0 to turn it off; otherwise it will be a much paler version of what you want, as the tint is set at 33% by default!)

Other mods in screenshot: Modded font used in the accompanying screenshots are Final Fantasy NES (by myself, a replication of the font used in Final Fantasy's NES release). You can find more information on PR font modding here, and you can find the font in my Dual Font Pack - NES and PSP(-ish) Fonts mod (it's the "Classic" option). Several screenshots were also made using a slightly modified version of the CRT part of FiveFiveFiver's LCD and CRT Presets for Reshade.