7 Colors

What is it?: A puzzle/strategy/board game, 1991, DOS (EGA or VGA), Amiga, and NEC PC-98.
What computer or emulator will it run on?: Any PC with the right graphic adapter. Playing under Windows has its advantages since there is no way to exit the game.
Similar Games: Space Invader, Color Lines, SameGame.

This game might be named 7 Colors (filenames are 7COLORS.*) or just Colors, as the modest monochrome text title screen suggests. I will stick to 7 Colors, since it is more descriptive. It was basically a French remake of Filler for international distribution by Infogrames. The main differences between the two games:

Filler has some text, 7 Colors has none.
Filler runs in EGA only, 7 Colors supports VGA too.
Nevertheless Filler has the more appealing graphics, and a better menu.
When using the mouse, 7 Colors has an arrow cursor, allowing you to point anywhere, while Filler has a frame cursor locked on the seven color diamonds.
You do not conquer diamonds completely surrounded by your own in Filler.

On the whole, Filler is nicer to look at, but 7 Colors is easier to play, especially if you don't know Russian.

The two opponents (two human players, or human against the computer, even computer vs. computer matches are possible, but somehow pointless) start in diagonally opposite corners. At each turn, they can turn their field into any color except the one of the opponent, thus conquering any adjacent diamonds of this color, and any that are completely surrounded by their own, or by their own and the border of the playing field. Does this sound confusing? 7 Colors is easier to play than to explain.

7 Colors can be played in high-resolution EGA or VGA, and it is the only game I know where this choice affects gameplay more than looks: under VGA, the graphics are exactly the same, but the playing field is larger. The game has a nice, though distracting, classical music score which requires an AdLib card (genuine Soundblasters can play it, modern onboard chips emulating a Soundblaster can't). Marco Gusy has figured out most of it:

Bach: Suite for cello solo in G
Bach: Inventio 1 in C
Bach: Inventio 1 in C minor
Bach: Bandinerie (orchestra suite in B minor)
Bach: Siciliano (sonata for flute)
Mozart: Sinfonia 40 in G minor

There is only one piece missing. He suspects it might be Mozart, too. If you know what it is, drop him a line.

PC-98

The NEC PC-98 version, ported by Hot-B and released 1992, had a nicer title screen. Here, the title is The 7 Colors. In gameplay it looked just the same.

Atari ST?

Usually you will find 7 Colors listed as available for the Atari ST as well. The only evidence that I have ever seen for this is a pre-release poster. While it is not impossible, it seems unlikely for the following reasons:

No screenshot, diskshot or boxshot has ever been posted anywhere.
Neither Atari Legend nor Little Green Desktop have an entry for this game.

Most likely Cameleon is the only Filler-type game for the Atari ST.

Links

Filler
Filler	90	Dmitry Pashkov
Filler for Macintosh	92	Lev Possajennikov
Fillers	95	Oleg Sergeyev
Filler for Windows		Alexander Vikulin
Cameleon		Toni Lönnberg
Cameleon98	98	Jari Komppa
Space Invader	99	Dmitriy Iassenev