This thread will hopefully be a combination of many useful links for Emperor: RotmK. If you find any other links of importance, please let the community know below and I'll add them to the post!

Widescreen Patch:
* You can download it here: http://www.wsgf.org/dr/emperor-rise-middle-kingdom/en
** Note the download will likely be blocked by your web browser. You can either use a browser like Edge, or follow the instructions in this video: https://www.youtube.com/watch?v=rec-ObU39YI&t=369s
* If you don't want to temporarily utilise another browser to obtain the download from WSGF, you can use this mega.co.nz link to obtain the Emperor patch: https://mega.nz/#F!vdp3GQQQ!PsUjKeBYfzvP7TK7MMkDkA

Let's Plays and Walkthroughs: There are many of them out there: I've linked a selection of them here (at least the ones that are the most helpful). Notes for each are provided in brackets for each LP). I have deliberately not included LP's/walkthroughs completed below Hard: this is because the game has almost no challenge below Hard due to the engine level changes.
* Hard Playthrough by Sajuuk's Let's Play's (commentated in full 1080p HD):
https://www.youtube.com/playlist?list=PLMZTavui8rFb3nFHnOoSKAsllKzR7giEE
* Hard Playthrough by Blxz (commentated in 1080p HD, completed):
https://www.youtube.com/playlist?list=PLQHP0zMn0jEkrivFJV90G5iAA6c-XqYcr
* Hard Playthrough by Game Destroyer (no commentary and limited sounds):
https://www.youtube.com/playlist?list=PL7P01OLgA9b0L0wW2m2vNUfOAylAL-Q_j
* Very Hard Playthrough by GamerZakh (commentated, but currently incomplete):
https://www.youtube.com/playlist?list=PLYVqUDxY6COjpD4bCNJabF8DZXVjzK_R2

Useful Guides/Info:
* Emperor Heaven (a great place to get information on everything, including some user created guides and custom campaigns): http://emperor.heavengames.com

* Impressions Games Wiki (user-created wiki with guides for all missions, though incomplete): http://impressionsgames.wikia.com

* Does that opening movie get annoying to play and skip after a while? Emperor allows you to disable it completely! Edit Emperor.ini in the install directory and change "PlayIntroMovie=yes" to "PlayIntroMovie=no". The game will now just skip the intro movie entirely!
** NOTE: Doing this particular tweak may solve random glitches with sound. See this thread for more information:
https://www.gog.com/forum/emperor_rise_of_the_middle_kingdom/stuttering_sound/post4

* Playing below Hard difficulty is ill advised: much of the challenge of playing the game is only found at Hard. At Normal difficulty, there is a slight challenge, but not that much and anything below Normal is just boring/uneventful. It is strongly recommend for new players to begin at Hard: you will learn much more about the game by doing so. :)

* If you install the game using GOG Galaxy, it might do odd things with the game. It is recommended to install the game using the older (but more reliable) GOG Downloader: more information can be found here:
https://www.gog.com/forum/emperor_rise_of_the_middle_kingdom/buttons_wont_click/post4

* Finished the campaign and want a challenge? Gwelio, a staff member on HeavenGames, has created many intriguing and tough campaigns for players! See the following link for the full list: http://caesar3.heavengames.com/cgi-bin/caeforumscgi/display.cgi?action=st&fn=23&tn=7587&st=recent&f=23,7587,0,20

Language Packs: If you want to play the game in your native language, then check this section for links to the correct language pack! NOTE: Back up your existing language pack files BEFORE changing them, in case of bugs!
* German: https://www.gog.com/forum/emperor_rise_of_the_middle_kingdom/german_language_pack
* French: https://www.gog.com/forum/emperor_rise_of_the_middle_kingdom/french_language

Known Bugs and Fixes:
* My screen goes black on the main menu after loading the game!
** If you are able to hear all game music and sounds, but the screen is black, you have an overlay enabled. Disable any and all overlays and reload the game. More info: https://www.gog.com/forum/emperor_rise_of_the_middle_kingdom/black_screen

* The mouse cursor position is off compared to the button placement
** This is caused by DPI settings. The fix is to disable scaling on high DPI settings. More info:
https://www.gog.com/forum/emperor_rise_of_the_middle_kingdom/mouse_cursor_off

If anyone is too worried about browser blocking the wsgf.org download of the Widescreen fix, you can can get the same Emperor widescreen fix (and also widescreen fixes for other city builder games) from the mega.nz link found in this Reddit thread:
www.reddit.com/r/impressionsgames/comments/3d0ckz/widescreen_fixes_some_links_are_down/

Thanks for posting that, I've added it into the OP :)

Thank you for posting this. Now, I can play one of my favorite game in widescreen!
The only downside is that the type is a lot smaller and harder to read. But, I think I will put up with that so I can see so much more of my map activity at once!

So how do I install?

Which patch of emperor is the gog version?

Only one patch was ever made for Emperor. It's already provided on the GOG.com version. Follow the instructions in the video link I provided for the WS patch: it applies to both.

A simplistic version:
1) Compare the DATA image files in the RAR with that in the install DATA folder.
2) Create a folder in DATA (at install location) called "Original" and move the files that match those in the RAR to that Original.
3) Create a folder called "HD" and extract all the DATA image files from the RAR for the resolution you want to "HD"
4) Rename the Emperor.exe to Emperor_original.exe in the main install directly
5) Copy the Emperor.exe for the resolution you want from the RAR to the main install directly.
6) Copy all the images from the "HD" folder you just made into the DATA folder.
7) Start the game normally.

If the game freezes on "Defining the borders", you didn't copy all the required image files as needed.

You are probably doing it wrongly. I tried it yesterday and it worked just fine following my own instructions. Restore the original files, and try again. The buttons should be clickable if you chose the right resolution you wanted.

It would be better to create a thread in the forum so we can discuss this better. This thread is more for just linking useful things, not so much for getting support. :)

I've added links to the German and French language packs to the opening post. If more are linked to, post here and I'll add it to the OP :)

Thanks!

No matter what I do my cursor is always in the wrong place. And since you have to be IN game to change the res I can't even get it to 1024x768!

*EDIT* Never mind - trying the GOG downloader fix

*EDIT 2* Nope! I tried getting it using the downloader and my cursor is STILL always off. Is there any way at all to fix this?

Check the bottom of the opening post, I listed a fix that worked for another user with mouse action being off compared to mouse position :)

If it doesn't work, make a new thread so we can help more clearly :)

Are those files on mega.nz safe to install?. I have downloade them but not sure if i should install them.

They are quite safe, it's just the game files modified a little bit to support bigger resolutions. If they weren't safe, I think someone would have raised it by now, given the widescreen patch for Emperor has existed long before the game made its way onto GOG :P