Early Footage
The images are from GameSpot, and the UK manual, kindly scanned by Galvatron.
There isn't a prisoner there in the final, the guard tower has been raised by one tile, and a box had been added.
The "PRESS A BUTTON" text is yellow in the final, and white in the prerelease.
Not only is the font slightly chunkier, but Set Up is listed after Continue here, nor is the amount of continues left noted.
Firstly, the selection icon is an arrow in the scan, but is a tank shell in the final. The font is, once again, different, and what's interesting is that the music goes up to 16 there, while the highest the music selection goes to in the final is 9. The explanation for that may be in the description: "[MUSIC] Allows playback of the game's soundtrack music, etc." I guess that "etc." means sound effects, so that would increase the number of sounds.
This was taken from a Spanish magazine review on the game. The colours seem pretty different (although, as I've said many times before, probably a compression error), and the most notable differences are how the cyan colours are murky green in the prerelease, along with the orange sky becoming violent red.
Back-of-the-box bonanza with a red tank, blue health bar, and some minor design changes. The longer health bar is due to S-Continue or something. Once again, cheers to Galvatron for the scan.
From the UK box's back again, with the green life bar, and I believe this is from the first level, but considering a lot of the plane levels look the same, I can't tell. Either way, there's an area very similar to this in the final, except that bigger cannon isn't there.
That soldier isn't there in the final, and that turret closest to the ground is slightly inside of the mound it's on, unlike the prerelease image, where it's placed properly.
The colours seem vaguely different (everything is tinted green), although that's probably just the scan's fault. The pipes and whatnot at the sides seem to be more detailed and different compared to the final.
No real differences here, other than the very bizarre colours, like the final's purple wall being an odd blue/green, and the life metre an olive colour.