How hard are Bach inventions?
Bach's inventions are solid early-advanced level pieces. They're written in two parts, which means each hand is playing a melody. These inventions are a great preparation for the more difficult Bach pieces that involve more than two voices (his fugues are in 3-4 parts).
Should I play Bach inventions?
Playing Bach's 2-part inventions is the fastest way to learn a considerable amount of musical elements, composition and piano technique, touches, phrasing, and art while playing beautiful, well-constructed and inspiring short pieces of music.