Yeahhh I think many of us feel the same way (basically if you travel to the beginning of the thread, a lot of people were complaining this is basically just an AZL clone). It's fine with me, esp since I love Siren's artwork and the genre.
Just sorta sucks because the character models' poses look near identical to AZL and the sex scenes are basically just cut-pasted from AZL (well, they're new but hell, I remember the beginning of AZL's development, and many of the CG scenes available now--the bath scene and gloryhole scenes--look eerily familiar). Even the characters are just the same so far--archetypal busty blond MILF and punk "sister" character. If Patreon didn't prohibit incest, I'm betting Siren would've just kept their relations as "mom" and "sister" as originally intended. The plot doesn't seem too much different either, but eh, if everyone likes it...
For me, the worst part is that ZR is only a side project (and is intended to be short), so it'll progress even SLOWER than AZL; I'm thinking this eventually rots in development purgatory, and will be lucky to suffer AZL's fate.