I lol'd so hard, truly epic
Is the same as saying
"I lol'd so hard, truly surpasses the ordinary"
And
The Harry Potter one was truly epic.
Is the same as saying
"The Harry potter one was truly impressive"
I see nothing wrong with those statements, unless you are defining epic as an adjective for size, in which case it is no longer used in the context stated.
Heck, even you used it improperly.
Thunder Quake sounds like an epic shooting/racing type game.