How I Built a Block Puzzle Game with React Native and Expo

How I Built a Block Puzzle Game with React Native and Expo A few weeks ago, I launched my first mobile game — a block puzzle called Blockbeam. It's an 8x8 grid where you drag colorful blocks, fill rows and columns, and chase high scores. Simple concept, but building it taught me a lot about React Native's capabilities beyond typical CRUD apps. Here's what I learned. Why React Native for Games? Most mobile games are built with Unity or native code. But for a 2D puzzle game, React Native is surprisingly capable. The game doesn't need 60fps 3D rendering — it needs gesture handling, state management, and smooth animations. React Native handles all three well. The key stack: Expo SDK 54 — managed workflow, over-the-air updates, zero native config react-native-reanimated — 60fps drag animations react-native-gesture-handler — PanResponder for drag-and-drop react-native-svg — block rendering AsyncStorage — game state persistence The Puzzle Engine The core of any block puzzle is the board state. I used a flat 64-element array for the 8x8 grid: const BOARD = 8 ; const CELLS = BOARD * BOARD ; // 64 type Board = number []; // 0 = empty, 1-7 = block colors Piece placement is straightforward: check if all target cells are empty, fill them, then scan for complete rows and columns to clear. The interesting part was the "greedy solver" I built for the auto-play bot. It tries every piece in every position and picks the move that clears the most lines: for ( const piece of tray ) { for ( let r = 0 ; r <= BOARD - piece . h ; r ++ ) { for ( let c = 0 ; c <= BOARD - piece . w ; c ++ ) { if ( ! canPlace ( board , piece , r , c )) continue ; const score = simulateClear ( board , piece , r , c ); if ( score > bestScore ) { /* pick this move */ } } } } Drag and Drop with PanResponder The trickiest part was the drag mechanic. Each tray piece has a PanResponder that tracks touch position and renders a floating ghost. On release, it calculates the nearest cell position: const anchor = { col : M