Remember to check and adjust the in-game settings according to your preferences; especially the key bindings.

Running Drakan after installing the Community Patch for the first time assigns the keybindings quite differently than what is listed in the game manual.
One of the main reasons for that is ergonomy - it appears that no particular level of thought has gone into creating the original defaults, with a lot of the frequently-used commands assigned to keys which are out of reach from the left hand's normal position.
Another reason is that the original defaults use the relatively uncommon ESDF layout, as opposed to the prevalent WASD arrangement - and they then totally squander that opportunity by not making use of most of the keys immediately surrounding ESDF; a highly questionable design decision.

The new defaults for the game controller should work properly with an XBox-compatible gamepad, the control scheme being broadly similar to the one in Drakan: The Ancients' Gates.
However, it's not possible to make the control scheme 100% identical, since some commands are specific to either the PC or PS2 version of the Riot Engine - eg. target lock is not available in Drakan:OOTF.

--------------------

To play the fanmade singleplayer levels: hold SHIFT while clicking the shortcut to start Drakan. This will bring up the "Riot Engine Options" window, instead of starting Drakan directly.
Click the "Developer" tab, tick the "Enable developer mode" box, then click OK to actually start Drakan.
While in Developer Mode, clicking "New Game" will instead open a list of all the installed levels.

To select a difficulty level when running in Developer Mode, hold CTRL while clicking "New Game".

--------------------

It's generally OK to set all the graphic quality settings to their maximum, even on relatively low-end systems; this is a 1999 game, after all.

If you find that Drakan appears overall too dark to play comfortably on your display device, turning up the gamma setting in the game options should help.

Volume adjustment: unfortunately, due to Drakan's engine limitations, it isn't possible to adjust the speech volume independently of the other sound effects.
Because of this, a music volume setting of around 40-50% is recommended for the optimal listening experience.

--------------------

nVidia users: some nVidia GPUs cause graphical artifacts to appear on bump-mapped surfaces, when Bump Mapping is enabled in the Riot Engine Options.
This usually manifests as graphical corruption on the surface of bodies of water, although Arokh can also be affected by this bug.

There are only 2 known solutions: either use the optional dgVoodoo2 DirectX wrapper (which fixes the problem completely), or disable Bump Mapping in the Riot Engine Options window.

Note that disabling Bump Mapping will alter the appearance of both water surfaces and Arokh's scales; generally speaking, they look better with Bump Mapping enabled, although that's a matter of preference.

--------------------

SLI/CrossFire users: if you experience unexpected crashes/BSODs with Drakan, make sure to disable SLI/CrossFire for Drakan.exe - it can't make any use of multiple GPUs anyway, and it suffers from known stability problems on multi-GPU systems unless SLI/CrossFire is disabled in the game's profile.

Windows 10 users: because of the constant Windows updates, Drakan's compatibility with Windows 10 tends to vary quite randomly.
Also, Windows 10 may erroneuosly declare some of the game's files, especially Drakan.exe and/or DrakanServer.exe, as being "potentially harmful"; this is a false positive, and needs to be manually set to ignore and run the game anyway.
A similar problem happens with some brands of antivirus/antimalware software; if that happens, add the Drakan installation directory to the exclusion list, and remember to restore any files that might have been quarantined by the software.

If you encounter any stability issues, or Drakan simply fails to start at all, try the following steps first:
 - set Drakan.exe to "Run as administrator" in the compatibility properties tab,
 - set the compatibility mode for Drakan.exe to "Windows XP" or older,
 - check your antivirus to see if it isn't falsely detecting Drakan as harmful, 
 - also check the AV quarantine area and restore any Drakan files that might have ended up there.

--------------------

Onboard (integrated) graphics adapter users: on some newer systems with both a dedicated graphics adapter as well as a non-disabled integrated adapter present, the dedicated adapter might not be selectable as a graphical output device in the Riot Engine Options.
This is a known issue with Drakan, due to it being a pre-DirectX9 game.
The only possible fix is to use the (included) dgVoodoo2 DirectX wrapper, which provides a workaround for that limitation.

NOTE: Selecting any level of antialiasing in dgVoodoo2 results in the GUI text being blurred slightly, due to the way it applies the antialiasing effect.
There is no fix for this, short of disabling antialiasing altogether; however, that causes the overall graphical quality to degrade significantly.

--------------------

Multiplayer connectivity issues:

If you can't see any currently active servers appear in the server list, or they appear to be offline even while they are in fact active - this is typically caused by Drakan getting blocked by your firewall. You need to configure the firewall to allow Drakan both TCP and UDP connectivity.

A list of the public servers which are currently online can be found at the following location:
http://www.qtracker.com/server_list_details.php?game=drakan
NOTE: that list updates relatively slowly; there can be up to a few minutes of delay after starting up a server, before it becomes visible there.

Servers refusing connection due to "invalid or corrupt files": that happens when the game data files (including the level files) aren't exactly identical on both the server and client sides.
This is usually caused by a mismatch between the Drakan patch versions on both machines, or - far more uncommonly - by accidentally overwriting some of the level and/or database files through incorrect usage of the Level Editor.

Hosting multiplayer games from behind a router or NAT requires setting up port forwarding first. 
There's a guide on how to do that on the Arokh's Lair forums (https://arokhslair.net/forum/viewtopic.php?f=2&t=3363).

Note that your ISP may also be using NAT, in which case you need to contact them to set up port forwarding on their side, as well. Good ISPs will either do that for free, or charge only a nominal fee for such a service.
Keep in mind that if there's more than 1 router/NAT between Drakan and the Internet, then EVERY device in the routing chain needs to be correctly set up with port forwarding, or it won't work at all!

--------------------

Additional content in the Community Patch:

Drakan soundtrack in the {INSTALLDIR}\Soundtrack folder. It's also linked to from the Start Menu.

The optional mods can be found in the {INSTALLDIR}\Mods folder.
Be careful with them though, they could break things. Depending on what files they replace, some cannot be mixed together unless you use the editing tools.
Character model mods also tend to break savegames!

Also included in the Mods folder is the alternate ending patch, which replaces the original ending with a fanmade version, while staying consistent with the events of both Drakan games. 
Note that applying this patch may cause some of the multiplayer maps to stop working!

There are some pre-defined level-list files included for the multiplayer maps - these aren't intended to be fed directly to the game server, but rather as a reference to aid in creating custom level lists. Check out {INSTALLDIR}\Multiplayer folder.

Registry settings for the game (graphics and developer settings), 10th Anniversary Mod and editing tools can be reset manually using the supplied Reset_All_Registry_Settings.reg file.
Remaining settings are stored in Drakan.cfg in your Documents folder, in "My Games\Drakan".

Editing tools are located in {INSTALLDIR}\Editor folder.

Drakan 10th Anniversary Mod can be found in {INSTALLDIR}\Mod10th folder.
Note that this mod is included mostly for completeness only, since it's rather poorly optimized - the performance isn't too great, even on very powerful modern systems, and it's plagued by many unfixed bugs. In particular, it requires disabling "Bump Mapping" in Drakan options to avoid severe graphical corruption/artifacts.

Also, the 10th Anniversary Mod is NOT compatible with multiplayer servers - because of the different (and VERY outdated) version of Drakan.exe it uses, multiplayer servers will refuse any and all connections when running this mod!

--------------------

Running Drakan on Linux (information courtesy of Discord user hemebond):

Officially, the Community Patch is not supported on Linux systems.
However, apparently it can be made to work regardless, with some extra effort.

Although it might start and work correctly, the performance suffers significantly compared to running Drakan in native Windows on the same hardware, due to the processing power overhead incurred by WINE. 
This is particularly obvious in some of the fanmade levels, especially in those with relatively high polygon count; the stock Drakan maps aren't affected nearly as badly.
Read the next section below for a possible fix though.

Unfortunately, providing a detailed step-by-step guide for running Drakan on Linux is beyond the scope of this document.
Therefore, only the most important information is listed here, under the assumption that most Linux users are already familiar with WINE.

The prerequisites are, primarily:

1. Drakan.exe needs to be run from the game directory for it to work properly.
An example command string is as follows:
~/.local/share/wineprefixes/Drakan/drive_c/Program Files/Psygnosis/Drakan$ WINEPREFIX=~/.local/share/wineprefixes/Drakan wine C:\\Program\ Files\\Psygnosis\\Drakan\\Drakan.exe

2. It's important to use winetricks to install the appropriate DirectX components, like directmusic and dinput.
Crashing as it goes into the main menu is because of missing directmusic.
Keyboard not working anywhere (including in main menu) means missing dinput.

--------------------

Possible fix for poor performance when running Drakan on Linux (thanks UCyborg!):

Drakan has been runnable on Linux through WINE for quite a while now, with some manual tweaking required by the user for correct, but slowish results. Not anymore! 

Recent development of the DXVK project now allow Drakan to run at much better speed when chained together with dgVoodoo2. 
This requires a modern AMD or NVIDIA graphics card, with support for Vulkan API with recent drivers, latest development version of WINE, both dgVoodoo2 and DXVK's DLLs placed in proper locations with correct DLL override settings.

Download link for the DXVK project:
https://github.com/doitsujin/dxvk