I read that Spectral is not actually a Netflix original, but a movie produced by Universal and intended for theatrically release that kept getting shelved until Netflix acquired it. That explains the big budget that went into the special effects.
I personally found it quite underwhelming. I didn't mind the concept, derivative as it was, and the first half features some genuine tension and excitement; the second half however went downhill fast thanks to some truly absurd plot points and holes that utterly shattered my suspension of disbelief. Moreover, the whole thing felt mechanical and lacked heart, not to mention any semblance of character development. I guess it's an ok sci-fi flick, but I expected better.