Grimrock

I have need of many levels in my mod... but not all levels are full of game objects. Some levels are just there to connect lower to upper levels, and have a small part of the map on that level used by tiles .. / north to south / east to west / etc (like a big building with many rooms)

Does it hurt the game performance of you have like 50 levels in your mod this way ?

In Grimrock 1, 3 levels were updated per frame regardless of the total number of levels. I expect Grimrock 2 works similarly.

Aye, the updates to levels it similar to LoG 1. I think there is even a post about it around here.

You can actually experience it live in the game: toss a spell into a teleporter leading into another level and jump right after it. Due to the slower update of other levels you'll very likely run into your own spell and take damage.

Anyway. The performance on the current level is most influenced by graphical things. Lights, shadows, reflections, flying projectiles and such. Since on the other levels no graphics are rendered there any running scripts and spawning of stuff (monster, projectiles, spells ..) are prolly the most performance impacts.

The behavior I see in Grimrock 2 is that all adjacent levels to the level the party is on are updated but at a much slower rate. This would include monster thinking and moving, projectile flying, doors opening and closing, everything. A level is adjacent if it is no more than one level away in any direction (X, Y or Z).

Any level more than one level away is not updated at all. Because of this, there is no performance impact in having many levels in your dungeon.