Need help with grammar

Hello everybody.

I have troubles with the following two sentences. Could you please check them for grammar mistakes?

«After he has finished giving orders, he exits order-phase, letting the in-game time run. Now all the units are simultaneously executing their orders until an interruption happens, invoking the order-phase for the player whose unit had generated the interruption.»

Thanks in advance.

Aren't you pretending to be not good at grammar?

I am trying to be good.

It looks fine gramatically, but I'm not sure that it makes sense as I don't fully understand the content.

Wow. I can't believe it.
And what about the last clause in Past Perfect («had generated»)? Can I use another tense in there, or is it the only correct?