When you already have played the game before in an older version and updated to a newer version with new blocks that use new textures, the new blocks would look invisible, and may or may not have collision depending on the block type. 

• Steps to fix the issue:

1. Press "windows" key + R and type "%appdata%". It will open a roaming folder.
2. Navigate to ".world_game" folder then "Resources" folder.
3. Delete the Textures folder. (back it up if you have your own custom textures placed inside)
4. Run Game or if it is already on, press the "Reload Textures" button inside the main or pause menu.

This will no longer be an issue if I completely rework my texture loading system. Though right now, the main focus is gameplay.