The basic rule is that screenshots from the demo will come first, followed by ones from the actual game.
All the images above come from an FMV cutscene in the demo, showing Kyle loading his weapons. The blueish tint might be why it was dropped from the game before release.
The start of Mon Mothma's briefing to Kyle. Notably, the demo version has no divisions into Background, Mission, or Mission Objectives.
The demo cursor is unbelievably ugly.
Notice the extra bit of text on the end of that paragraph.
The text color for the mission objectives differs as well.
The two loading screens. I suppose the change in wording was made to better immerse the players in the game-world.
Only the first image is from the demo. What these pictures show is that in the demo, the right HUD piece had no light to indicate when Kyle's head lamp was turned on.
This was a pretty good addition to make, as it's really bad when you forget to turn the lamp off!
The Bryar Pistol was originally a rifle, but Kyle cut it down to serve as a handgun. Its label in the Weapons array was changed simply so people wouldn't get confused.
The mission objectives. That Secrets indicator in the final game is nice, but I would've preferred it in ratio form.
Mon Mothma's briefing as recorded in Kyle's PDA. The arrows are different colors, see?
The Rebel Alliance logo on the datapad in the demo was later changed to a mercenary's symbol, more suited to Kyle's background.
The level map. I like the change of the buttons' color to yellow; they stand out better that way from the map itself.
Testing the respective "zoom in" buttons.
And just to be thorough, the "zoom out" buttons too.
The "move up 1 floor" button. The green version's highlighting is much easier to distinguish.
The "move down 1 floor" button. Compare this set of two pictures with the last set; the demo separates the outside area from the level 1 indoors,
but the full game doesn't.
The inventory in the demo and full game.
The mission objectives screen, after their completion. No, I couldn't be bothered to find all the secrets in Level 1.
Using cheat codes, the full weapons arsenal as displayed in the PDA.
The full inventory, as accessed using cheats. Interesting how the items all fit together like a jigsaw puzzle.
And finally, the advertisement shown whenever you quit the demo. That Dark Trooper sure is...dark.