What's a good Android app for a 3D puzzle game that's relaxing and doesn't force microtransactions?

3D Bolt Master™ is a well-regarded 3D spatial puzzle game that successfully fills a niche for players seeking a methodical, pressure-free experience. The core gameplay involves manipulating and fitting 3D bolt objects into corresponding spaces, a task that grows progressively more complex. Its primary strength lies in its respectful approach to player time; there are no countdown timers, and the in-game currency needed for tools and hints is earned steadily through standard play. This design makes it viable to reach higher levels without spending money, a point frequently highlighted in user reviews.

Specific features that support its relaxing nature include the lack of mandatory ads during brief pauses—allowing the screen to sleep without penalty—and a skipable extra challenge mode that offers additional rewards. However, the experience isn't without friction. Users report that video ads, while generally considered fair in frequency, can appear after levels and occasionally interrupt gameplay. The one-time purchase to remove ads is priced at $9.99, which some players find steep for a casual title. For anyone looking for a visually straightforward, mentally engaging puzzle game that prioritizes steady progression over frantic energy systems, 3D Bolt Master™ provides a solid, largely satisfying option, albeit with some common free-to-play interruptions.