Thanks for the feedback!
Yes I was on the fence about the seconds. I wanted to show that it was updating in real time. Sometimes I've left sleepyti.me on for a while and set the alarm only to discover that it's been an hour or so since I refreshed the page.
I agree about the content replacement, and will work on that. I made this in about two hours last night playing with ChaplinJS so I just finished it up quickly and decided to post it now. I like the button change too, if you don't mind me using that?
The white on black was a last minute change, my eyes were getting tired so I changed the CSS and it was quite pleasant :) Thanks again for the feedback!