torchlight-2
The first playthrough brings you from level 1 to 51. After you start NG+, the game starts over at level 51.
How far does this playthrough bring you? Will you get all the way to level 100 on the second playthrough, or does it stop somewhere and make way for a third playthrough with the same character with even more difficult foes?
How many repetitions of NG+ exist, and what are the appropriate level ranges for each?
Upon accepting and finishing the quest that gives you NG+, you will be booted back to the initial character loading screen (where you can switch between characters etc.).
You can then choose to Resume to play on your character, that is now in NG+ mode.
This means its level will remain the same, aswell as the skills and stats.
All your progress however is lost, so you start with a new world and the same quests you did before. You do however still have access to the Mapworks by using any Waypoint Portal.
You are not prompted to change the difficulty mode at any time (a pity in my eyes), so your difficulty setting is carried over.
You can ofcourse always change the difficulty setting if you want, as explained in this post.
Easy enough to test, or so I thought. My initial approach was to create as many characters as possible, but at a count of 25 I quit:
A second approach was to dig in the Runic Games forums and even there, nothing seemed to be found about the maximum amount of characters one can have.
Until I found this post: What is the Maximum Number of Characters I Can Have?. The answer to that post : unlimited. There seems to be no cap on the amount of characters you can have and there doesn't seem to be an immediate cap on the amount of characters the game can display.
However, that post is for Torchlight, NOT Torchlight II.
In my opinion though, it's fair to assume that the same still holds true for Torchlight II. Or at least that many that you really won't need that many.
Best Answer
So yeah, it appears there's no end to how many times you can NG+ — but there's also no point.
These numbers are fixed. If your character has a higher level than 51 at the start of NG+ (my Engineer was level 54 when he made the jump), the game will still start at level 51 and monsters will adjust in their allotted level brackets accordingly.
Before you start planning your wonderful adventure towards and beyond NG+∞, you want to keep in mind that your character can only play in multiplayer with other players in the same New Game Plus tier. That means you will need to start a new character at level 1 to play with friends who are still midway their first quest.