Getting bombarded by spam that Akismet is not catching

For the past few months, I’ve been getting bombarded by comments that are essentially essays about various things such as NFL jerseys, gambling, and bunch of other random stuff. I would paste the whole thing here but it is literally like 1,200 words.

Any idea how to combat this? I have basically turned on require registration to comment while disabling anyone can register option. So while I’m not getting any spam comments now, I also do not get any legitimate comments either.

Any help would be appreciated!