Well, with a Metacritic score of only 68, you apparently didn't miss much but if you want the game on Steam, it needs to be submitted to Valve by whoever bought the IP when THQ went pop. Put on your detective hat, find out, contact them and convince them it'd be a good idea to put their game on Steam.

How do you know it was an amazing game if you never played it?

Fans of the Punisher like it, I remember reading reviews of the game when it first came out, it was dark, gritty, gorey and violent, Punisher.
The Deadpool game got low reviews, but anyone of whom is a fan of Deadpool loved it, I thought it was amazing.
Do Valve not look into adding games for us? Or do we have to contact the companies for them?

引用自 Punisher：

Fans of the Punisher like it

Not entirely true. Really not true at all. Are you just going on the Hasselhoff effect?

引用自 Punisher：

Do Valve not look into adding games for us?

No, they do not. People bring their games to Valve.

One thing worth considering - developers/publishers don't live in a vacuum. They're well aware of Steam so if an eight year old game isn't on the store, they either don't think it's worth the time/effort/money supporting it or there's a legal issue involved.

引用自 Skoardy：

One thing worth considering - developers/publishers don't live in a vacuum. They're well aware of Steam so if an eight year old game isn't on the store, they either don't think it's worth the time/effort/money supporting it or there's a legal issue involved.

I suppose that explains why they have newer titles like Saints Row and Red Faction, but some of their older titles, like The Punisher
So, would I have to personally make a request to Volition? It seems weird that it's practically the only game they've made that's not on here.

引用自 Punisher：

So, would I have to personally make a request to Volition? It seems weird that it's practically the only game they've made that's not on here.

I'm not sure Deep Silver bought the license rights for The Punisher when they purchased Volition. It might have been in one of the lots that Nordic Games bought.

It still might be worth contacting Volition to see if they can point you in the right direction.