I've built an MVP of **Block World** - a 2D sandbox platformer focusing on the core mechanic of mining and building. Here's what's included:

**Core Features:**
- **Procedurally generated terrain** - Rolling hills with grass, dirt, stone, and rare gold ore
- **Block mining** - Hold click to mine blocks with a progress bar (different blocks have different break times)
- **Block placing** - Right-click to place blocks from your inventory
- **Inventory system** - 4 block types (dirt, stone, wood, gold) with stack counts
- **Scoring** - Earn points for mining (10 pts normal, 100 pts for gold)
- **Physics** - Full platformer movement with jumping and collisions

**Controls:**
- **WASD/Arrows**: Move & Jump
- **Left-click + Hold**: Mine blocks
- **Right-click**: Place selected block
- **1-4 Keys**: Select block type
- **Click inventory slots**: Select block type

**Next Ideas:**
1. **Multiplayer Sync** - Add WebSocket-based real-time player positions and world state synchronization so multiple players can build together
2. **Crafting System** - Combine resources (3 stone → pickaxe for faster mining, wood + gold → treasure chest for storage)

**Ready to level up your game? Pick one and let's build it!**