Version 5 is now live and can be downloaded from the main page. There's a new devlog that needs to be made to explain it all, so better start working on it 'suppose. Until then, this version includes:

• the previous "jungle" generation from the last devlog
• minecarts and rails
• flying debris from mining, which can also drop items when mined

And some fixes from the last update:

• Projectiles now can hit minecarts (as well as the player themselves)
• Rocks now spawn when mining
• Rocks can now spawn flint when destroyed
• minor code restructuring for display tags (mob bar)
• Bunch of quick bug fixes for the live version
• Debris now mostly spawn to the sides around the player, at a more constant size
• And other bits forgot to mention