Zokudu-
What types of games do you like?
We could all reccomend Super Game 17 to you, but if it is from a genre you hate, it won't do much for you no matter how good it is. I don't think I've seen a bad game given a reccomendation in this thread(outside of MGS4- but a lot of people love it for some reason), but if you are into say go kart style racing Mod Nation Racer is a game you absolutely won't want to miss(but avoid it like the plague if you aren't into them).
I would say Demons Souls is nigh *entirely* combo based, just not in the button mashing sequence style of GoW or DMC. Take even a simple mob like a blue eyed Tower Knight- walk up to him and hit him once and then back off. You could probably do that for an hour or so(do they ever run out of grass?) and never kill him- or- you can roll up to him, knock his shield out of his way and then do a combo strafing around him and likely kill him in a few seconds. Most of the mobs in Demon's Souls are comparable, you need to do something to deal with their defense before you can really do any damage at all to them. This is very different then GoW or DMC which use combos heavily, but don't rely on them for basic gameplay nearly as much as Demon's Souls.
And then you have the differing levels of upgrades and how that ties in with strategy(ie- swapping between a heavy bleed effect weapon after you get the bleed on to a straight dmg weapon, or swapping from something like the Shredding Spear to a real dmg dealing choice once you get their armor beat down).