Have a separate RPG Maker category for RPG Maker 2000/2003

Start with the existing RPG Maker detection logic referenced in #393 and compare it with the proposed RPG_RT.ldb and RPG_RT.lmt signals. Clarify whether RPG Maker 2000 and 2003 should remain combined, then define acceptance criteria for a separate category and validate them against the listed Steam examples.

Some reference to the engine, such as the developer site or a wikipedia article.

This request may seem redundant, as a RPG Maker category already exists, and that an attempt to separate the different RPG Maker categories was already made in #393 and rejected/not approved/not merged, due to the different engines being simply considered as revisions rather than different versions, thus not needing any distinction.

Nonetheless, while some versions may seem similar due to being close engines, with a first version made and then an upgrade/revision (2000 and 2003; VX and VX Ace; MV and MZ), the versions are still significantly different, offering different experiences (different resolutions, different methods of coding, some versions have plugins while others not, etc.).

In my case, I'm a contributor at EasyRPG (https://github.com/EasyRPG), and tl;dr, EasyRPG has an interpreter that allows to run games that are made on RPG Maker 2000, 2003, as well as original games made using EasyRPG. Being able to know which games run using RPG Maker 2000 or RPG Maker 2003 on Steam is very useful to make use of the engine, and while currently, Steam Database provides a RPG Maker category for the engine, this serves no purpose in this case as the RPG Maker category has over 4,000 games, with most being made on the more recent versions of the engine, meaning it is impossible to find entries using the wanted RPG Maker versions without manually checking each of the 4,000 entries.

As I do not know if keeping RPG Maker a single engine category is something that is set in stone, and that I do not follow closely Steam Database development, I'm opening this issue both as a discussion in case it would pose an issue, and has something I would be interested in: if I can help on any matter on this, I will try to and could try to create a pull request, though I'm not familiar with other RPG Maker versions so I wouldn't be able to help much on them, sadly.

SteamDB links

You can already look at what was mentioned in #393 . Just to add some entries (could have added some more but I would need to recheck first):

2000:
https://store.steampowered.com/app/418190/Helens_Mysterious_Castle/
https://store.steampowered.com/app/3754530/PURPLEARC/
https://store.steampowered.com/app/316840/The_Sacred_Tears_TRUE/

2003:
https://store.steampowered.com/app/2017620/Beloved_Rapture/
https://store.steampowered.com/app/810470/Black_Dream_Plus/
https://store.steampowered.com/app/756150/Born_Tubi_Wild/

Possible way to detect it

Work on the engine detection was already worked on in #393 , so it can already start from here, but I would say it is not entirely satisfying: for a game, the file RPG_RT.exe does not need to be present or named like this, and RPG_RT.ini will 99.9% of the time be there, but could be missing as the only thing it is needed for is mentioning that the external assets of the engine are not required (it being missing would prevent boot to those that have not installed it).

A more satisfying detection would be to check if the files RPG_RT.ldb and RPG_RT.lmt are present, as those are needed files for a game to run which cannot be renamed or removed, and that, to my knowledge, should not cause conflicts with other engines.

In my case, I do not think a distinction between the 2000 and 2003 versions are needed, but if one were needed, then reusing the 2003 detection logic from #393 (.r3proj, /BattleCharSet/, /BattleWeapon/) is doable and can be the solution, if you at least add /System2/; if you want to be extra, you can also add /Frame/ and /Battle2/, as well as detecting if ultimate_rt_eb.dll is present.
This is not a completely foolproof solution for RPG Maker 2003, as:

• .r3proj is from recent versions of the engine, and is not used by the game itself, so it can be removed by the developer
• ultimate_rt_eb.dll is only from recent versions of the engine, which, while everyone uses the recent version to be able to legally publish, is ditched by some patched versions of the engine
• /BattleCharSet/, /BattleWeapon/, /Battle2/ only need to exist if you use the battle system of the game, which is not the case for every game
• /Frame/ only need to exist if you continuously display a picture on the screen while playing, which is a feature absolutely never used
  Only real exception is /System2/: on boot, the game checks if a file from /System2/ that has to be set is valid, so it needs to exist in any case (a developer could always set the file to point to another directory but as it requires digging to do that nobody does it).