Possibly the biggest difference is that 23 Words continues with the next word if you fail to get a word within 30 seconds. When you have attempted all 23 words it will present you with results like this.
You found 21/23 words Top 7% of players today.
I'm pretty sure it didn't used to continue after getting one wrong.
I played it and the other word nerd games every day for a few months, but eventually they get repetitive, which I suppose any generated game will.
You're right, it changed a few months ago. I find it more enjoyable now that you can continue to the end.
Possibly the biggest difference is that 23 Words continues with the next word if you fail to get a word within 30 seconds. When you have attempted all 23 words it will present you with results like this.