I like it, but I find it frustrating that zen mode is timed and that I have to login to access past puzzles - I don't find it enjoyable or worth it with these constrains.
Many players who love this mode are also fans of blitz chess. Curious if you're into rapid/bullet modes in general or that's not really your cup of tea.
Edit: ah, you mean in zen mode - true, it’s there. Then again, the timer is still running, which I find annoying.