がってんなら - what kind of contraction am I dealing with in this sentence?

Question

I'm trying to understand how to parse the がってんなら in this sentence (it's from Tales of Vesperia, in case anyone's curious):

帝国がってんなら、
この旅の間にも
何度か見てきたろ？

This is how it's translated in the English version of the game:

Haven't you already seen what
the empire's capable of several
times on this trip already?

The second part of the sentence is easy enough, but I just can't wrap my head around the first part. Is it short for 帝国があっているなら or something? And what would that translate to literally? Is there some bit that's omitted that I should be able to infer from context?

Answer 1

帝国がってんなら、

It looks like a contracted pronunciation of 帝国がと言うのなら。

～というのなら → ～ってのなら → ～ってんなら
(The particle って can be the colloquial version of という.)

I think the sentence literally means:

『帝国が』と言うのなら、
If you mean "The empire (did...),"
この旅の間にも
on this trip, too
何度か見てきたろ？
you've already seen (what it's capable of) several times, haven't you?