"Morroblivion is additional content - a 'mod' or an add-on - for the popular PC video game The Elder Scrolls IV: Oblivion, released by Bethesda Softworks in 2006. The Morroblivion project seeks to merge the content from the previous game of the series, The Elder Scrolls III: Morrowind, into the more modern gaming engine of Oblivion.
While ownership of both games is required to play, the player only actually plays Morroblivion using the Oblivion game, and not the older Morrowind game. This means that the user interface, combat, graphics, and system requirements for the Morroblivion mod are all those of Oblivion, and NOT Morrowind."
I played it years ago and it was ok. But I found the monsters were way overpowered. Basically everything had at least 100 hit points added to it, including rats. It made the low levels really tough.
I tried it again recently, but could not get the newer version to work. Oh well.