Complex sentence: Given the point in time, the film pushed Japanese animation technology to the limit, making this a large scale major project involving a total of 13,590 staff, yet only taking 8 months to finish.
Split into simpler sentences: Given the point in time, the film pushed Japanese animation technology to the limit. The film was a large scale major project, involving a total of 13,590 staff; surprisingly, it only took eight months to finish.