SCP-6666 is to be kept within a 2.4x2.4 metre steel room,
First, "meter", second, is there a reason for a specific size of the room?
The door is to be made of a thick titanium alloy
This goes back to the former. If you include specific measurements, you either do it all the way or not at all. Except if you give sufficient explanation for such measurements. It's just a matter of consistancy.
A puppets mask is worn upon the subjects face
First, puppet's, second, it seems… vague. Puppet is a broad term, please specify. It can also add a bit of character to your scip, so that the reader can put a face on it.
it is the {REDACTED} of the {REDACTED} upon further asking it simply states that there was not just {REDACTED} but actually five.
And here we go. [REDACTED] all over the place. Stop it, you're killing your baby! (wow, that was overly dramatic…) [REDACTED] and [EXPUNGED] are not plot-hole glue, they are precise and delicate tools to add mistery and provoke the reader to fill it in by themselves.
Just adding [REDACTED] in each sentence, sometimes miltiple in one sentence, just breaks the flow and makes these sentences meaningless.
wrapping the subject in {REDACTED} allowing SCP-6666 to {REDACTED}, See {REDACTED}.
This is a great example. You've technically removed everything interesting from this sentence, giving nothing in exchange. The reader has too little data to fill it in. It just falls apart, adding nothing to the story. Hell, you've even redacted a possible addenda in this paragraph!
There's a nice essay on how to use [REDACTED] and [EXPUNGED] here. Go and check it out. These are powerful tools, and with great power comes great responsibility!