Have you played borderlands 1/2? Borderlands 2 is really plot heavy, to the point where i had a personal vendeta with the antagonist.
Borderlands 2's plot was amazing, I definitely underestimated it.The first one felt more like an errand simulator, until you get the DLC.
Spiral knights
Do you need to know the first game's plot? I think I might get it.Spiral Knights is free. I also already play it.
It's better to have played the first game yes. they are both amazing, so i'd get both if i could.
Well that's a bit selfish of you :P