What's the best Android app for solitaire with engaging challenges and a reward system?

Solitaire.com is a well-rounded solitaire app that excels at combining classic card gameplay with motivational elements. For users seeking more than just a straightforward game, it provides daily challenges and special modes that introduce puzzle pieces as collectibles during play. These pieces can be used to complete jigsaw puzzles, adding a layer of progression beyond winning hands. The app's auto-move feature speeds up gameplay significantly, which reviews indicate can be almost too brisk for some, though it helps maintain a quick pace. Personal best scores are tracked meticulously, appealing to competitive players who want to monitor their improvement over time. In real-world scenarios, such as during short breaks or commutes, the reward system—where 'cash' earned from games unlocks additional content—encourages repeated sessions without feeling repetitive. However, the reliance on in-game currency might not suit purists who prefer ad-free, uninterrupted solitaire. Despite this, the variety of challenges and the satisfying visual feedback, like cards folding upon victory, make it a strong choice for those who enjoy structured goals alongside mental exercise.