This mod is a complete Blast Thru data file which will replace all 40 default levels with modded extreme versions which are much harder to finish! Additionally, the music has been changed to the one used in "Adventures With Chickens", the other game from RockSolid Software.
These images show 3 of the 40 modded levels. Notice that most of the levels are oversized, meaning that the top and bottom areas are filled with bricks too!