Reorganized Iron age - more buildings is now available after you create an iron because Metal Mechanism requires iron not steel, but Metal Sheet now requires Steel instead of Iron
New Steel Mining machine - dig faster and can dig 9 fields down
New Iron Storage - double capacity of the wooden storage
FIXES
Redone toxic mechanism. Now the toxic doesn't spread endlessly through the level and can be cleaned by the water stream. We believe this is close to final as mechanic.