It needs some polishing, there are quite annoying aspects:
1) Mandatory gender and country? Seriously, why? Even e-mail shouldn't be mandatory IMO. Hitting 'Enter' on register/login forms doesn't work as submit, I need to grab the mouse for that (especially annoying on a programming-related site)
2) The "How are programs run" section is completely useless. It's never mentioned how is my code actually invoked, just how it is compiled (when applicable). Let's take C for example, it says 'gcc contestx.c -o contestx.c'. Assuming the argument to '-o' is a typo, this way of compilation includes linking... so it seems I'll need `int main()` to avoid linker errors, but what's to be in `main`, I'm never told. I'm just assuming .c code is just `-c` and `dlopen`ed, but I'm not sure, since 15 minutes after submitting a solution, there's still no feedback.
Other nitpickery includes email validation code that's not clickable (okay, this is arguably a good thing) and other stupid memes implemented on the site like asking for the email twice or showing me my local time in the upper-right corner even though all other times on the site are displayed in the server's time zone (e.g. upper-right corner shows 16:45, but the solution I just sent is shown as submitted at 7:45)