Complex sentence: The first volume is available with a pack-in Panda-Z toy 3 (8cm) tall... and to judge from a short sequence in the opening credits, this toy is as big as the "giant" robot is.
Split into simpler sentences: The first volume is available with a pack-in Panda-Z toy 3 (8cm) tall. Judging from a short sequence in the opening credits, this toy is as big as the "giant" robot is.