There is no per-browser changes on the page at all (since browser detection is a dead-end anyway), and I just checked here from several browsers, and it does continue to work fine.
Nothing at all on the download page has changed in quite some time... I'm leaving it mostly untouched, until I can launch the new site (leaner, meaner, more functionality, all hand-written backend).
Make sure you're not hitting /dl/ with your browser, as that will result in a 403 error. You'll want to hit the following link:
http://www.plkr.org/dl
NOT
http://www.plkr.org/dl/
I'm responsive to any emails/bugs if you find something, but at this point, I can't see any problems with the page, and checking the stats, I see a few thousand hits per-hour with a 200 status for that page.
I also see people downloading the tarballs, zip files, etc. in the logs, which are linked from that page. If the page was blank, they wouldn't be able to download them...
Let me know if you find something, and I'll look into it on this end.