Primary by Chong Kok Seng is a puzzle game for Android.

As the captain of Starship Primary, your mission is to push back the invading alien ships by launching deadly weapons at them. You launch the weapons by marking the fuel tiles underneath them. You can mark a rectangular block of fuel tiles if the fuel tiles at the four corners of the block have the same color. The weapons at your disposal are time bombs that freeze the alien ships at their path, and missile rockets that push them back. Once pushed outside your primary perimeter, the alien ships are destroyed. The fuel tiles you mark also generate additional income. Use the income to buy more missile rockets and time bombs. If the block you mark triggers a bonus goal, your weapons get a significant power-up. As you level up, you face different alien ships, and they can counter attacks with their own weapons! For example, their shutdown rockets can make some fuel tiles unselectable! The higher the level, the deadlier their attacks become.