To be honest, I thought it would look much worse. I would say it is even acceptable if you design for a website with a tech-savvy audience.

Yeah, that looks like it degrades rather gracefully. As long as (1) the text is still readable, and (2) the buttons are clickable, I say people should just go for it.

With a little more effort you should even be able to make them look a bit more like buttons in older browsers or Internet Explorer.

IE8 looks the same.