Home Improvement achievement in Kingdom Rush

Contributed on 8 July 2023. (easy achievement)

Level 3 towers are unlocked once mission 4 Twin River Pass is reached, and this achievement can be unlocked on that mission on Easy difficulty before ever losing a heart.
This refers to upgrading the towers during play, not the upgrade tab on the map screen.

On the Map screen, select the ENCYCLOPEDIA to see the different towers with their upgrades, and advanced upgrades.

The 4 basic tower types and their three upgrades are:

ARCHER TOWER -> MARKSMAN -> SHARPSHOOTER .

MILITIA BARRACKS -> FOOTMAN -> KNIGHTS .

MAGE TOWER -> ADEPT -> WIZARD.

DWARVEN BOMBARD -> ARTILLERY -> HOWITZER .

To upgrade a tower during a mission, have enough gold to purchase and then click on a tower. That brings up the radial wheel. Use to select the upgrade at the top and press . Place, and upgrade each of the 4 different towers 2x each and achievement unlocked. Congrats!

Courtesy of gamertag: E vee dub, for the love of the game.