"The heartless Shivans emerged through subspace near Earth, harboring technology light years ahead of anything seen before. "
Tsk, tsk... Light years are a measure of distance! Ha!

And your point is?
"Lightyears ahead of...." is just an exaggerated version of "Miles ahead of....", which is just as valid.

I know, I was joking...

you were jokingly owned then

Not listening, lalalalalalala!

Well, in a sense OP has a point. Or at least he led me to a point.
In the blurb there is talk about subspace and exiting near Earth. When you throw in light years as a metaphor of being ahead in a field (technology in this case) in a space flying game you are somewhat using a bad metaphor. Or at least using it in a bad place. I mean, it's not inconceivable that at some point in the game the term will actually come in as a measure of distance so I would have recommended leaving out of a blurb and going with something less confusing, given the context.
Perhaps just years ahead would have done the job. Add decade or century if further emphasis needs to be added. It's a completely irrelevant nitpick on my part, I know, but it's a bit clumsy.

The Shivans are years ahead... the Shivans are miles ahead... the Shivans are lightyears ahead. I don't see the problem, myself. At worst, I could accuse the word "lightyear" of being a bad pun, but that's all.

It's like when Han Solo claimed that his Millennium Falcon "made the Kessel Run in less than twelve parsecs".

Lol. I noticed that mistake as well.

Aaaand you would be wrong. That was retconned into being right in one of the EU novels; Since Kessel's defining feature is a cluster of Black Holes that you have to navigate around, finding the shortest route around that cluster is an awesome feat of navigating, and of course a test for the ship's endurance.