If the work has the same layout or scenarios as the original, but better visuals and minor tweaks to the original gameplay; it's a remaster.
If it has different structure or different kind of gameplay than that of the original, it's a remake.
Those are my two cents. How different must the stuff or gameplay need to be to qualify as a remake, that I don't know. For example, Xenoblade DE introduces a new way to deal with the side quests compared to the original, which in turn results in a different way to approach a significant portion of the game. Is that kind of stuff enough to qualify it as a remake?
My bet with The_Liquid_Laser: I think the Switch won't surpass the PS2 as the best selling system of all time. If it does, I'll play a game of a list that The_Liquid_Laser will provide, I will have to play it for 50 hours or complete it, whatever comes first.
