Do you need to use custom objects?

I might make an area in knytt experiment, and I can make my own tileset and gradient, but when it comes to animation I'm no good at all. What's more each frame has to be a separate image, and the settings like animation speed can't be changed. So my question is, do you need to use custom objects or can you just use the standard ones? And can you use the objects under custom objects in the editor or not? I would like to use the water/waterfall but I'm not sure if only Nifflas can since their under custom objects and he made them as far as I know.

You can use as many or as few standard or custom objects as you want. However, the more custom content your level contains, the more likely it will be to get into the Experimental database. If all the stuff in the level is custom, there's a chance it'll get into the Normal database.

There shouldn't be anything under "custom objects" in KE. When you start a new project, it creates a folder for the project, and in this folder should be another folder called Sprites. All the stuff in the Sprites folder is the standard objects.

I meant there's a place in the editor where the objects are and some of them say custom objects. Thanks for the answer. Can you use the default custom objects too?

Yes.

However, the more custom content your level contains, the more likely it will be to get into the Experimental database. If all the stuff in the level is custom, there's a chance it'll get into the Normal database.

As far as I know, the people that are accepting levels nowadays don't care about that; they put it in whatever database pleases them, with no regard for the rules Nifflas laid down.  I've seen levels in Normal with no custom content.

As you can imagine, I'm very irkful about it.