Hi, to answer a few of the questions raised, you can download the shareware files from 3d realms' site, I think:
3D Realms Site: Duke Nukem 3D Atomic Edition
Use the 3dduke13.zip - v1.3d Shareware Episode (5785k) link.
(I can't test the link here at work, some of the others are dead, but you could search for the filenames on Google).
Next, you need to unpack the Duke3d.grp file, this is the game data. Basically, unzip the file above and double-click on the .exe file in it. This is an old DOS file, so if it fails to launch, right-click on it, choose properties, then compatibility and just tick the box "Run this program in compatibility mode for:" and leave it at Windows 95.
Let it install into C:\Duke3d, then go in and take the Duke3d.grp file out and drop it onto a storage card, along with the other files from spvDuke3d. That's all you need to do to install it. Tap on spvDuke3d.exe in File Manager to start the game.

Now here's the bad news as far as using the buttons on the X51v. They seem to be software buttons, not hardware (at least, except for the D-Pad and the button in the centre). Sooo, if you map one of them as the Escape key, they all act as the escape key... Very, very irritating. I've given up and I'm using a BT keyboard, instead...
P.S. you can get a basic version working, if you set Landscape mode to 0, set the screen height to 430, the screen width to 480 and set Jump to the centre button (i.e. Enter), set Up on the D-pad as forward and open.
Why? Because on version 0.4g of spvDuke3d, there's a tiny X in a box at the top right hand corner of the screen. Tapping this with the stylus opens the main menu. And with the screen set in that way, you can tap the keyboard icon at the bottom of most screens on the Axim, to launch the soft keyboard.
I still haven't managed to make it work as an input device in the main game, but it does work in the save game screen, which means you can type in a name for a save game! Without a name, the game won't save the file! Oh, and I cannot get scan code mapping working
This is my Config file (I've just put in the bits I changed).
I set the Cache memory to 26000, as 2600 wasn't enough and I set the Platform Timer Hz to 600 in a vain attempt to get better frame rates.
FXDevice = 13 and MusicDevice = 13 kills the sound, it's supposed to give better performance, i haven't noticed any difference:
[Setup]
SetupVersion = "1.3D"
spvDuke3DVersion = "0.4g"
spvDuke3DPortAuthor = "Roozbeh GHolizadeh"
spvDuke3DPortHome = "www.spv3d.com"
[Engine Setup]
UsingGapi = 1
ShowSIPButton = 1
Platform_Timer_HZ = 600
LandscapeMode = 0
CacheMemory = "26000"
ShowFPS = 1
ShowKeyCodes = 1
TickRate = 135
TicksPerFrame = 26
ScanCodeMapping = 0
Alt_EscapeKey = ""
Timidity_Dir = "\SD Card\spvDuke3D\timidity"
[Screen Setup]
ScreenMode = 0
ScreenWidth = 480
ScreenHeight = 430
Shadows = 1
Password = ""
Detail = 1
Tilt = 0
Messages = 1
Out = 0
ScreenSize = 12
ScreenGamma = 16
[Sound Setup]
FXDevice = 13
MusicDevice = 13
FXVolume = 0
MusicVolume = 0
NumVoices = 4
NumChannels = 1
NumBits = 16
MixRate = 12000
ReverseStereo = 0
SoundToggle = 1
VoiceToggle = 1
AmbienceToggle = 1
MusicToggle = 1
[KeyDefinitions_Landscape0]
Move_Forward = "Up" ""
Move_Backward = "Down" ""
Turn_Left = "Left" ""
Turn_Right = "Right" ""
Strafe = "" ""
Fire = "" ""
Open = "Up" ""
Run = "LShift" "RShift"
AutoRun = "0" ""
Jump = "Enter" ""
Crouch = "" ""
Look_Up = "" ""
Look_Down = "" ""
Look_Left = "Insert" ""
Look_Right = "Delete" ""
Strafe_Left = "4" ""
Strafe_Right = "6" ""
Aim_Up = "2" ""
Aim_Down = "8" ""
Inventory = "J" ""
Inventory_Left = "G" ""
Inventory_Right = "M" ""
Holo_Duke = "" ""
Jetpack = "" ""
NightVision = "" ""
MedKit = "" ""
TurnAround = "W" ""
SendMessage = "" ""
Map = "Record" ""
Shrink_Screen = "-" "Kpad-"
Enlarge_Screen = "=" "Kpad+"
Center_View = "KPad5" ""
Holster_Weapon = "ScrLck" ""
Show_Opponents_Weapon = "" ""
Map_Follow_Mode = "SoftKey1" ""
See_Coop_View = "" ""
Mouse_Aiming = "" ""
Toggle_Crosshair = "" ""
Steroids = "" ""
Quick_Kick = "`" ""
Next_Weapon = "" ""
Previous_Weapon = "r" ""
Original_F1 = "1" ""
Original_F2 = "" ""
Original_F3 = "" ""
Original_F4 = "" ""
Original_F5 = "" ""
Original_F6 = "" ""
Original_F7 = "" ""
Original_F8 = "" ""
Original_F9 = "" ""
Original_F10 = "" ""
Multi1 = "Call" ""
[Misc]
Executions = 87
RunMode = 1
Crosshairs = 1
WeaponChoice0 = 3
WeaponChoice1 = 4
WeaponChoice2 = 5
WeaponChoice3 = 7
WeaponChoice4 = 8
WeaponChoice5 = 6
WeaponChoice6 = 0
WeaponChoice7 = 2
WeaponChoice8 = 9
WeaponChoice9 = 1
This is the original page with details on all the settings:
spvDuke3d [v0.4c]...with Sound/Music now! - MoDaCo