How to progress through Megabonk stages

Defeating a Megabonk stage boss and entering the opened portal advances players to the next stage. If no portal appears, the current tier is complete, requiring selection of a higher tier for progression. Progression involves completing stages within tiers of maps like Forest or Desert. Tiers represent difficulty levels, with portals to subsequent stages appearing in Tiers 2 and 3 after defeating bosses. The Desert map unlocks by reaching Forest Tier 2, Stage 2 with character CL4NK, who requires the Revolver obtained after defeating 7,500 enemies.