This option effectively transforms the assertive sentence into an exclamatory one by incorporating the exclamatory word "Bravo!" to express excitement and admiration for the person's excellent performance. The original sentence simply states the fact that the person played well, while the exclamatory version adds an emotional layer of praise.

Option 1, "You played well!", is also an exclamatory sentence, but it does not convey as much enthusiasm as Option 2.

Option 3, "What have you played!", is not grammatically correct and does not express the desired meaning.

Option 4, "How you played well!", is grammatically correct but sounds awkward and does not convey the same level of excitement as Option 2.

Therefore, Option 2, "Bravo! You played very well!", is the most appropriate choice for effectively converting the assertive sentence into an exclamatory one.