I love this idea as it encourages you to test ideas and approaches you might not ever consider in day to day frontend development.
Can you save along the way? I wasn't ready to submit, but my browser died and I lost what I'd done.
Also, it would be nice to have a bare minimum for markup validation. Perhaps mark validating HTML entries that render fine with a green tick so competitors know the baseline. I'd think 150 characters validating beats 150 characters not validating, yeahAlex Walker has used this product for one day.
Quite a few really great and entertaining challenges. • Solving a challenge feels awesome; finding a 'better' solution feels even better.
There is no way back once you got hooked. • Reducing the character count can get incredibly hacky. *
* Don't get me wrong… it's super awesome to see what can be done with CSS and browser behavior. To get the best score possible one needs to ignore quality tho. :DAndreas Grafen has used this product for one week.