Replayability question

[Nyah]

Hey,
Something isn't clear for me, what do you gain when you finish successfully a run? i believe it's the Relics and you can have three.

ok, but it seems to me that it won't really be enough to maintain a will to play in the long run and a separate pvp mode would be nice to have (even if i'm not so much into it, it would be good to have).
Maybe i'm missing something but i don't understand how so limited rewards will keep most of players playing.
Can someone clarify it?

edit: thinking about it maybe the relics are locked to a character so you got to earn other relics for other characters which means more replayability