If the puzzle you solved
before you solved
the puzzle you solved
after you solved
the puzzle you solved
before you solved this one, was harder than
the puzzle you solved
after you solved
the puzzle you solved
before you solved this one, was
the puzzle you solved
before you solved
this one harder than
this one?

Taking the sentence one clause at a time:
The one you did after the one you did before this one IS this one.

In other words:
“…the puzzle you solved after you solved the puzzle you solved before you solved this one” is this one.

Hence, the question may be rephrased this way:
“If the puzzle you solved before this one was harder than this one, was the puzzle you solved before this one harder than this one?”

Obviously, the answer to this question is Yes.