The first kind of sequential removal puzzles that I will discuss is the computer game Chain Shot! and its derivatives. Chain Shot! was developed originally by Kuniaki Moribe in 1985 for the Fujitsu FM-8/7 series, and ported to UNIX under the name of Same Game in 1992 by Eiji Fukumoto. This puzzle is probably one of the most ported/cloned puzzle programs available for computers, known under many different names (see a list of pre-2000 ports on wikipedia). Later, it got ported to Windows Mobile where the same game is known as either Jawbreaker, Bubble Breaker, Bubblet or Bubblets. And now it has come to the iPhone, and again the same game is popping up over and over again. The basic principle is actually really nice (Biedl et al. 2001 is an analysis of its complexity is, showing that it is NP complete), but do we really need dozens of versions of this?
Same Game is played on a rectangular field initially filled with typically 4 or 5 differently colored blocks placed at random. By selecting a group of adjoining blocks of the same color, a player may remove them from the screen. Blocks that are no longer supported by removed blocks will fall down, and a column without any blocks will be trimmed away by other columns always sliding to one side. The goal of the game is to remove as many blocks from the playing field as possible.
The following apps appear to be straightforward implementations of such classic Chain Shot! / SameGame (links redirect to iTunes). Unfortunately, none of them mentions the origin the game, a recurrent problem with puzzle implementations in the app store:
- Fart Bubbles (you guess right what happens when you remove blocks in this one…)
- 3D_cube (a Nissan promo app, shown here to up on the left)
- BPop (lite version) A screenshot of this one is shown the the right here.
- reMovem (lite version) A screenshot of this one is shown at the top right of this post.
- TKO Marbles, TKO Ornament Rush
- It is also one of the puzzles in the PuzzleManiak suite.
Various developers hit onto the same idea to enhance this puzzle by using the accelerometer that is available in the iPhone. By turning the iPhone, the blocks will fall to the side, reshuffling the blocks accordingly. This opens up more possibilities, but it does not necessarily make the puzzle clearer. The following apps offer SameGame with tilt (links redirect to iTunes):
As has become the norm in ports of SameGame, these puzzles all have slightly different implementations of the rules: there are different number of colors and different scoring schemes (normally the value of a group raises quadratically with the number of connected blocks). There are also a few aspects that seem new, as far as I know.
First, iSameGame and Quadrum:colors offer and option to only present fields that are completely solvable. In classic SameGame the blocks were placed randomly, and the goal was to end with as few as blocks possible. The idea to offer starting positions that can completely be removed sounds interesting, though I did not try it out yet. Second, BPop and Quadrum:colors offer blocks that vary in color. In BPop you can choose which color they should have, and in Quadrum:colors some blocks are multicolored, and can connect groups of differently colored blocks.
So, summarizing, Chain Shot! is a nice puzzle, so you might want to try out one of these on a lazy afternoon. Don’t expect too much puzzling depth in any of these implementation. I think that by carefully choosing layouts, the puzzle might actually become much more interesting. However, automatically generated layouts are of course much cheaper than tediously hand-picked carefully designed lay-outs!
[Update 11 January 2009] The SameGame implementation that is part of the PuzzleManiak suite of puzzles just became available as a standalone app: SameGameManiak. From the description it appears that this version has the objective to clear all blocks, not just as many as possible (as in the original).
[Update 22 January 2009] ClearItLite is yet another classic SameGame implementation. Why do we need 10 versions of this puzzle?
[Update 23 January 2009] I missed a SameGame variant that also uses tilting to reshuffle the blocks: CubeeCubee. Apparently, this app is already in the app store since november 2008.
[Update 4 February 2009] Another one using tilting: Action Bricks. This is the eighth SameGame version using the idea of tilting the iPhone, but still the developer claims in the blurb that this game is “bringing you [a] new puzzle experience on your iPhone/iPod Touch.”
[Update 25 February 2009] Another classic variant: PocketPop Revenge. Sliding to the side can be turned off, and emptied lines can be refilled. We have seen this all before. This one is a remake of an old Palm variant of SameGame.
[Update 1 March 2009] Another developer gives it a try (it’s just classic SameGame): Bubble Shot.
[Update 7 March 2009] Looks like another classic SameGame implementation, though with an emphasis on the background (sex sells…): SquareX.
[Update 12 March 2009] The ‘classic’ mode of Kascade seems to be a implementation of classic SameGame.
[Update 16 March 2009] Classic SameGame: PopStar!
[Update 24 April 2009] SameGame with tilting once again: BlocsNTurn Full.
[Update 7 May 2009] Classic SameGame: Bubble Lite
[Update 8 May 2009] SameGame with rotation: SkyeBlu
[Update 25 May 2009] Block-Out.
[Update 2 Juni 2009] Not Square – look very much like TapPuzzle mentioned above (from the same company as well).