Is there free building in this game?

[Warfield]

Or just the campaign / story? I mean, can I design my own dungeon and play endlessly?

[Alone in the dark]

Nope, there is as far as I remember only the campaign and skirmish modus.

[Warfield]

Thanks! Is skirmish against the AI or other players?

[Alone in the dark]

There are Modi against AI and others against other players.
But the Multiplayer is completly dead. If you have no friend who plays
this game with you there is no chance to find a game.

The part against the AI is just protect a NPC as long as possible, so
nothing that would take a lot of time.

But if this game is at -75 % even the campaign is worth a buy.
So just wait until it is on sale again...fullprice is too expansive.