Bug: Boom labs puzzle 4 of the last lethal set (Electra) won't load. It just stays stuck like in the screenshot below, I tried reloading a few times. I play on Android,
The Puzzle Lab Guide - Hearthstone - Icy Veins
Puzzle Lab - Hearthstone Wiki
Hearthstone: The Boomsday Project - Dr. Boom Lethal Puzzle Lab Solutions | Shacknews