TLDR; if CM rejects you, they may "ghost" you, rather than inform you.
A recruiter contacted me through LinkedIn in early October, before my latest job search began. We had a great conversation, discussing the opportunity; I sent my resume, and within a relatively short period of time I had a phone screening. They answered my questions about the company and position very thoroughly. The technical evaluation during that call was carried out effectively; my CSS skills did not quite meet their requirements, which we discussed. We signed off, and I waited to hear back.
I heard nothing for a week or two; the recruiter then let me know he returned from a vacation; then I heard nothing, again, for a few weeks.
By then, I'd begun my job search in earnest. I emailed the recruiter, asking for an update, and learned the position I applied for was no longer available— but a different position was. I was quickly sent a 24 hour coding challenge, which I dropped everything to complete. Submitting it was a little difficult— if ever CM asks you to submit a Git repo to them, you'll want to ZIP it up and send them a Dropbox link, as they apparently don't have Github accounts— and we all went on break for the winter holidays. Afterwards, they reached out to ask me to fix a bug, which took a couple hours. They implied that the submission was well received, and to "please standby for updates on the next round".
That was ten days ago; since then, I've received no word. I found a job elsewhere, and despite the admittedly exciting portions of this process, overall my dealings with CM have left me disappointed.
Reader— no matter who you are, you deserve to receive notice of your rejection. In my case, Critical Mass did not abide by that principle.