Spoiler Warning for S1E5-S1E6
Apparently Mom thinks it's easier to fly a weather balloon to stratosphere than make a simple Galileo telescope. And then somehow she's able to naked-eye observe a close-orbiting black hole, which would be cooking the planet with X-rays already, and have weird time dilation effects; see Greg Egan's Incandescence for a more plausible story of being that close to a black hole.
Then the claim that the trees have one growth ring… when these are clearly old-growth, decades to centuries worth, with moss, thick undergrowth, and years-rotting fallen trees as one would expect of Canadian forests.
A yearly cleansing by stellar fire would leave a mostly-sterile desert with fast-growing weeds and voracious predation by estivating animals, like Death Valley blossoming in a yearly monsoon season, not cool evergreens (even aside from the utter stupidity of Earth-like plants on an alien planet).
I guess I should give them credit for one scene where grass is digitally recolored from green to purple. A small token nod to "not Canada".
Dr Smith is increasingly awesome and terrible. I assume she knows how to pass as a therapist from years of being in therapy, and a half measure of con games and grifting. The shit she does to program Angela as a weapon is amazing. Knockout performance.
Penny's teen romance with Vijay is awkward and they're both quite terrible actors, and there's Vogon-quality poetry. I would love these scenes to be much shorter, or for them both to be eaten by eels, on-screen and slowly.
Don West, Argentine soap opera actor Ignacio Serricchio, has improved greatly from his annoying first few eps, good comic timing and enough schemes of his own going on to be interesting, and he plays off well against heroic Judy. Single-camera editing only works if you're meticulous about sets and wardrobe, however, and the St Christopher medallion he took from Dr Smith keeps appearing and vanishing around his neck, and the time of day keeps changing even when it's overcast, throughout a few of his scenes, which suggests these were fix-it shots on another day. Maybe Señor Soap isn't great at reading lines without multi-camera and a teleprompter?
The asshole politician, the snooty Japanese scientists, and dozen generic extras are less present and interesting than the CGI fairy moth thing. Utter failure for an "ensemble" show, it would be better if all these extras and the supposed crew of the Resolute died and left the Robinsons isolated.
I grew up watching reruns (a decade too late for original run) of the original Lost in Space, which was about the triangle of Dr Smith, Will, and the Robot, and the rest barely even had names, and it worked because Billy Mumy had enough charm and wit even as a kid to stand up to Jonathan Harris and Bob May. He could read a line of naïve dialog and then show the gears turning as Will figured out what Smith was doing. Which is to say, everything this show's Will is not capable of.
This Will Robinson has graduated from emotionless sociopath to harming his pet. He's gonna be a serial killer.