There is a disconnect between the ability to survive in and eventually dominate a biome and being able to beat the boss of that biome. Sadly beating the ill-designed bosses is a requirement, for the most part, in unlocking the next biome. However if you manage to sidestep the boss of a biome and partially exploit the next biome up you can then, in some cases, make the boss fight winnable without forcing your character into the 'intended' mold.

To be fair I should be clear; I like the game, I like the implementation of the biomes and their difficulties including the mini-bosses. I also absolutely hate the implementation of the progression roadblock biome bosses. I hate the design, the implementation, and the 'single track railroad' mindset behind them.

Eh well, nothing is perfect.