Army of Ruin
221 Achievements
GOG
Explosive Flask
Graveyard III - Complete the Stage with Storm Javelin
23.5%
How to unlock the Explosive Flask achievement in Army of Ruin - Definitive Guide
Nothing special here. The Storm Javelin is one of the starting weapons. Its evolution is one of the best for crowd control, so it should be no problem to beat this stage with it. Prioritize the elements for its evolution to make this as easy as possible, then just finish the stage.