BrainStrain is a free tile-matching app designed for Android users. This app is developed by PositronTech and falls under the Games category. The app aims to test your mental acuity by dragging the correct color or shape from the corners to match the word in the center target.

The app is excellent for young audiences to learn basic shapes and colors, but also challenging for all ages. It has many configurable options that allow fine-tuning for the perfect mental gym, from the size of the tiles to the speed of the timer. Additionally, the app includes a "BrainStrain" mode for the ultimate test!

BrainStrain is free to download and use, and it has no in-app purchases. The app uses simple banner ads, which are minimally intrusive. Also, a night mode is included to help with eye strain. Overall, BrainStrain is a great choice for those looking for a challenging tile-matching app that can help improve mental agility.