The game is best described as a cross between Tetris and Connect Four. Blocks of 2-3 colored gems drop from the top of the screen, and your objective to move and rotate them to line up with other gems of the same color. When the required number of gems are aligned (starting from 3, and increasing at higher levels), they disappear and you score points. You can create chain reactions when new lines are formed by dropped gems. Once you reach the required number of lines ("drops" in the game), you will move on to the next level.

So far it may not sound like the game is any different from Tetris. But the beauty is that the game introduces new gameplay elements as you play. At higher levels, you will come across rainbow blocks which can count as any color, and solid blocks which don't disappear. You can also trigger special affects by building up lines that exceed the minimum length required. These special affects range from making the bottom line disappear, removing all the solid blocks, removing all blocks of one color from the screen, and the spectacular "tornado" effect. Each new level either introduces new elements, or varies the requirements to make the game tougher. For instance, on some levels only diagonal blocks will count. One of the best features in the game is the save and restore facility. When it saves, it really saves your position - down to the exact positions of blocks on the screen. This makes Gemstorm ideal as a coffee-break game you can switch back and forth while working on the computer.

Overall, Gemstorm is a fun, accessible, and graphically pleasing Tetris variant. It may not look like much, but the game will certainly grow on you if you're a big Tetris fan. And with 100 levels, you won't need another reflex-oriented puzzler for quite some time. Highly recommended.