They can always use vanilla JJ2. After all they're only the default levels. I don't like bugs that defeat the point of something, and that added trouble to level designers to make boss sidekick spam (which sucks out all the challenge) unusable.

The boss sidekick spam trick is pretty easy to perform. Get hurt once, be at the boss, then hold on the down + jump button.

Being able to go through poles has always been a JJ2 bug.