Best and worst most extreme departures long running series have taken?

[Leynos]

Best. Ninja Gaiden 2004. Series had a nice run in the late 80s to early 90s from arcade to home console to handhelds. 2004 reboot was a great way to not only bring the series 3D to give it a new identity. It plays well even to this day and retained it's challenging nature of the older titles.

Worst. Yiaba Ninja Gaiden Z. What is this shit? While it does have a cool aesthetic. The gameplay is awful. AWFUL. Bad writing.  Annoying enemies. Not balanced well. Oh yeah sewer levels. For all the faults Ninja Gaiden 3 was. At least Razors Edge salvaged what they could and made a solid fun game out of it. Yaiba?  It's a car wreck where a puddle of flesh could not be identified as part of the NG family.