Does this game actually have Dungeons and Dragons ruleset?

Like the infinity engine games? Alignment, XP, Armor Class, THAC0, Multi/Dual Class, All those spells? I don't know how much has actually changed in D&D since those games came out.

Kind of? It's based off of 4th Edition, which was more combat heavy than the other editions, but the game itself is more Diablo-like than its predecessors.

There's been 2 whole revisions since the stuff like Baldurs Gate, which was based on AD&D2 rules. (Neverwinter Nights was based on D&D3e for the record) So yeah, to my knowledge this is based on the 4e rules. And probably the last gasp of 4th edition as D&D Next (what they are calling 5th edition) is currently being playtested.

There's been 2 whole revisions since the stuff like Baldurs Gate, which was based on AD&D2 rules. (Neverwinter Nights was based on D&D3e for the record) So yeah, to my knowledge this is based on the 4e rules. And probably the last gasp of 4th edition as D&D Next (what they are calling 5th edition) is currently being playtested.

It's "based" on 4e...but very loosely.

Very loosely based on 4e, so there are feats and skills, no Vancian magic. Encounter skills means they have cooldown, Dailies need a full meter to be used. The existing classes are based on classes in the first Player's Handbook. No Alignment, no THAC0, no multiclassing either.

Its based on a version of DnD. It is not like infinity engine games though. 4e moved more in a combat heavy direction and its systems are much more fit for an mmo style of play than the previous editions would be. If you like combat and things being more simplified then you might like it. I played the game a bit just to see what it was like and it reminded me more of diablo than any previous Dungeons and Dragons games like Neverwinter Nights or Baldurs Gate.