Many pictures (obviously not the ones depicting dinosaurs) are taken from Assyrian reliefs. This one, used in the first mission briefing, is from the Lion Hunt of Ashurbanipal. He hunted lions a lot.
Lion Hunt of Ashurbanipal
The second mission, where focus switches to buildings, has a photo of a street in ruined Pompeii. Via Abbondanza, the Street of Abundance, to be exact:
The seventh mission, where the player must repel the attack of wild Dinosaurs, is adorned with a T-Rex head. It is the prop from the Jurassic Park, of course!
Tyrannosaurus Rex Head from Jurassic Park
The eighth mission has this horse archer. It is, in fact, Ashurbanipal once more:Ashurbanipal Hunting ReliefA medal was made to commemorate all the lions he hunted I guess…
Some info from the museum:
– Limestone relief from the N. palace of Ashurbanipal at Nineveh, his capital.
– Ashurbanipal reigned from 668-626 BC.
– Ashurbanipal was the grandson of Sennacherib and son of Esarhaddon
– The detailed relief stands 63.5 cm (25 inches) tall.
– actual dimensions of the detail are w. 3 ft. 8 in. h. 1 ft. d. 8 3/4 in.
– The relief reveals a royal hunt for Gazelle, lions, and other animals
– The King of Assyria is on horseback with bow stretched
– The king’s servants are following behind with arrows and a spear
– The panel shows the King of Assyria with his attendants and horses
– From the Neo-Assyrian Period (1000-612 BC).
– Excavated at the site of ancient Nineveh (Kuyunjik) by H. Rassam about 1847.
– The royal hunt is seen throughout Assyrian history
– The theme of the hunt was very popular in Neo-Assyrian royal art.
– The Bible called Nimrod a mighty „hunter” before the LORD
– This stone panel was is currently at the British Museum.
– Nineveh (Kuyunjik) was Ashurbanipal’s capital city (Northern Iraq).
– Ashur-bani-pal was one of the most energetic and cruel of the Assyrian kings

The eleventh mission has this gate. You guessed it – lion hunt again:

Stone relief from the palace of AshurbanipalStone relief from the palace of Ashurbanipal, Spectators at a lion hunt climb a wooded hill surmounted by a stele. This scene has been regarded by some scholars as depicting the famous hanging gardens of Babylon.
Late Assyrian c 645 BC. Nineveh, Assyria, Ancient Iraq.

The other briefing images are either CGI from the game, or individual tribe reliefs.

And speaking of tribe reliefs, they are present in the outro screen:

Outro reliefsThe Koaka deity hand has been twisted by an artist, to better resemble a wing perhaps.
I spared him that fate the second time =)
Only the Romek image is missing, hiding in the shadows left of the Muspel ritual.
Or maybe they just teleported away.

The Masai and the Muspel have the same stone pattern in their interfaces, differing only in color… Suspicious!

masai and muspel

The Radumba background stone texture is the Tribestone, but green!

Radumba stonetribestone

Names from the PWAR.EXE file

It seems there was an early heads-up message planned for encountering noxious weed and mushrooms.
There are warnings (or …warings?) coded in pwar.exe file, which you can find using notepad++ for example.
They look like this in the code:

WARING – Poison plant
WARING – Toadstool

These are the names of all units in the game:

Commoner Muscle-man Warrior Constructor Elf Wizard Warlock Ranger Velociraptor Carrnotaurous Rhamphorhynchus Triceratops Diloposaurus Tyrannosaurus Brachiosaurus Centrosaurus Stauricosaurus Daemon Mammoth Musso Tiger Leopard Cur Nexious Weed Poisonous Mushroom

Apart from obvious typos, the curious thing is Brachiosaurus here. It is a hidden unit, with a whopping amount of health. You can cheat it by clicking to train a capturer in your sanctuary, then quickly changing to a barracks with a designated ctrl-number. It has no sprites so it is invisible – like the camo mutant from the Jurassic World film 😀

And yeah, also no idea on the Daemon, as there is a „Warlock” already. Maybe the warlock was intended to be a different kind of wizard, as it is in the sequel.

The prompts and names of spells, taken from the .exe file, are:

Framing-Ball target ? Roaring-Sound target ? Lighting target ? Ice magic target ?
Poison-Gas locate ? Fire-Dance Earthquake Self-destruction
Patient ? Patient ? Who protect ? Who protect ? Who resuscitation ?
Small Mapping Magic Grand Mapping Magic Space Shift locate ?