RudeGuy07 wrote:Having too few kind of enemies in a level will make it boring, especially if it's long, because you just see only those enemies in every part of the level.
It can also add to the atmosphere of a level. As I said, you shouldn't add NPCs just to increase the NPC variety.
RudeGuy07 wrote:I think you should just use about 8 different NPCs in every level, including basic enemies like goombas and koopas (though the number can raise, but 30 is just too much).
I don't think 8 specifically, I'd say about 10-15 is fine. It really depends on what NPCs fit with the theme of your level