Hi Cristian,
The tutorial is a good starting point, though I find it a bit easier to split the fade into two sequences. I create a FadeOut sequence that transitions from 0 to 1 on the fade track and a FadeIn sequence that transitions from 1 to 0. Then, you can add them into your level and wire it up to play before and after changing levels. Here’s an example:
I’m just reloading the same level here when the ‘K’ key is pressed, but you could copy the functionality into all of your levels so that they would handle the fade in and fade out appropriately.
There’s a bug that will be fixed in 4.13 where the default fade value wasn’t always being reset between sequencer shots, but I don’t think that would affect you when you’re loading a new level. If you’re still having trouble, let me know and I’ll investigate further.
Best,
Cody