Gem Twins is a skill puzzle game with classic pixelated arcade graphics. Two brothers are in search of adventure and floating plant bulbs across 27 stages (levels) of underground rooms. The brothers aren't exactly normal. They can turn themselves into gemstones. This gift is beneficial. It makes it easier for them to access difficult areas and bypass traps and obstacles. The player's objective is to direct their actions to reach each bulb goal across regular and speedrun modes.
The player can direct each of the twins to walk and jump. They can also direct one brother at a time to temporarily freeze in place on the ground or in the air. With this ability, they can create a narrow platform with one brother and then direct the second one to use the spot as a jump point when dealing with high walls, tiers and other obstacles. Since they can freeze a brother mid-jump, they can create this gemstone platform beyond ground level. They can create it at one or more points midway up the side of a wall.