For nearly every system Sega made, they had a version of Columns, their famous puzzle series. If you're not familiar with the Game Gear, but familiar with any other Sega system, you're still likely to know about this classic puzzle game.
This particular version, named Super Columns, was one of the later versions. I'm not really certain what qualifies it as super, and what makes other version of Columns not super, but the game delivers just what the title promises: onion-domes. Er, I mean, a puzzle game, that's NOT affiliated with Tetris in any way.
Columns is fun, despite my jibes, but for people who grew up on Tetris, this game might serve only to remind them of that old game, and make them desirous of their old Game Boy.
For the Sega half of the world, however, Super Columns is the same old, delightful game, involving pieces of three gems that come cascading down vertically, and making the player think to try to connect three similar shaped gems in a row, either on an angle or in a straight line.
The story mode is pretty weak, and its only good if you anticipate playing against another human opponents, so you want to improve you puzzle-combat skills. Beyond that, it's not like there's an interesting story or anything, but I guess no one was expecting there to be one.
There is that puzzle game staple called puzzle-mode, it's a mode where there's a more clearly defined objective than simply 'stay alive' or 'stay alive longer than the other guy' that might help keep things interesting. In this case, you're tasked with uncovering the flashing piece beneath the other jewels and eliminating it with two more gems of the same colour.
What it all boils down to is that if you're not embarrassed to whip out your enormous Game Gear in a public place when you're bored, then Super Columns makes for a good game to just plug in and play. I don't think I can stress enough that puzzle games, or perhaps strategy games, are the ideal entertainment for a portable medium.