u/Dry-Airline-2655

Hello. I'm not super seasoned in this game, but think I made quite a bit of progress. Now I feel stuck to the point where I'm having a hard time unlocking new stuff.

Quick recap: Been playing mostly with Poe, due to Garlic being such an effective starting weapon, and upgraded the ol' man with plenty of eggs, and have finished most (or all?) accomplishments up to the points stated below:

Where I sort of hit a wall:

1. Sketamari boss in Bone Zone. I can't seem to beat it. Stage is generally pretty brutal due to no floor chicken, but still manageable. Though I'm obviously lacking in tactics (or power) against this growing skeletal ball.
2. Boss Rash. Getting outpowered after a while and cannot seem to finish the level.
3. The Coop. Treacherously easy at first, but I'm soon getting swarmed by enemies and rooster bosses.

Way forward? What should I focus on beating first? Should I try a new approach, or test out some new heroes? I've unlocked so many of them, I feel unsure as to who to pick next.

EDIT: I should also add that I did unlock Adventures mode, but haven't played it more than once or twice. Is the way forward to play this mode more?