Soldam is a nice, fairly unique (Othello/Reversi/Tetris inspired), and very difficult obscure puzzle game (with GREAT music) developed by Jaleco in 1992. It was later ported to Game Boy (only in Japan) in 1993 and the versus mode characters, Rit and Tam from Rod Land, make a brief cameo appearance in the comical shooter, "Game Tengoku". The game is essentially a spinoff of Rod Land. The core concept of the game is to rotate drops of four and "sandwich" objects together to make lines of a single color, which can then be eliminated from the playing field. Making eliminations also creates a "Soldam" safety line at the bottom of the screen which is good for making vertical and diagonal colorswaps more easily. As you progress through the game, the drop speed will increase drastically and more colors will be thrown into the equation to complicate matters.
The game features three modes of play: Soldam (The Normal Endless Game), Sekiero (The Technical "Adventure" Game) and Versus (Where Rit and Tam fight for candy). Sekiero is the bulk of the game where you must complete sixty levels of drop madness while facing evil "Sekiero" foes along the way and powerful boss enemies. Sekiero differs from the other modes due to attacks from enemies, Sekiero orbs (which are nuisance drops that require two lines to clear or "Dekabura" to touch them), and collecting the letters for "EXTRA", which is the main strategy of the mode to get far while using as few credits as possible. When all the letters are gathered, a grand pixie will clear the playing field and give you bonus points depending on the amount of remaining lines you possess. The game is pretty nice visually, but features an amazing little soundtrack, composed inpart by Atsuyoshi Isemura, Yasuhiko Takashiba and Yasuyuki Suzuki. This is a video showing the first few levels of the game and defeating the first boss. Enjoy.