I still don't know why this wasn't just released straight to VOD. Probably a contract thing that it had to hit theaters first and they didn't care enough?
So, new mutant Moonstar gets orphaned and is sent to this "institution" where there are four other mutants also institutionalised, one mutant lady in charge, and... no-one else. Seriously, this is a thin cast. Yes, there are other people filling in momentary roles, but this is basically a small cast in not much larger than a locked room. ANYWAY, spooky stuff starts happening, and who is to blame? Is it the new mutant with psionic powers who just turned up? Nah, couldn't be. But hey, gives them a chance for things to happen, so we get scenes, and thus a movie.
Really, this is fine, but it certainly had a build up of "when will this get released? we need to reshoot! ... but we may or may not use those reshoots... eh, we'll get this out some time." I don't know what the full production hold up was, but I find it hard to believe it was seriously reconsidered often, and, as I said, should have just been dumped on VOD.
The performances are all right, and I often spent time trying to remember "which mutant is this?" Pro-tip, they never actually give them their mutant names, so don't hang around for that. And there's the hand puppet... booooooo! The effects are decent, but at this point that should be the default (and yet still so many effects that aren't good).
Given than director Josh Boone said "nah, don't worry about covid, go see this," well, screw him, this isn't that important. Just wait for it to finally get put out on VOD.