http://goofans.com/developers/addin-file-format/how-merge-two-or-more-go...
Of course, if you want to add dependencies between the levels so they have to be played in order, or if you want to add chapters, this is a whole different thing, but if you just want multiple levels per goomod, this is the way to go.

I will try with the mods - only for now but it will be handy to know how to make extra chapters Is it hard anyways?

Sure. To use more than one level, simply change (in addin.xml):

<level blahfsdf/>

<levels>
  <level blahfsdf/>
  <level blah2/>
</levels>

Unfortunately you can't make new chapters in WoG, only replace existing ones. Me and Albino Pokey are (barely) working on a guide on how to make them, but for now the best help you can find is here. Read that and you should understand how chapters work, that should allow you to replace existing ones with your own.

Oh great. I did NOT want to create new chapters, but when the tutorial is done can inform me.

That is possible and easy - I made about 2 packs but uploaded only 1 - it is not really necessary to use level pack cause then you realize it is pointless - better make a chapter (But I dunno how to make it)

Yes, i am also trying to find out how to make a chapter but that's a lot of work

There are several pages of how to make a chapter and all that is confusing. We would need an example like for the level packs. If you want to make a level pack it's simple - just follow instructions in one page (Search on goofans 'Merge' and clickon first link)

There's a sample chapter I made here. You can look around in the goomod at how it's put together, it might help in understanding how chapters work. You might also be able to use it as a template, replacing certain bits to make your own chapter.

Thank you! i wish i knew anything about xml coding - making a chapter requires xml coding right?

Yes, but it's fairly straightforward, since it isn't really a specific language. It's more just a type of syntax you can use for anything, and the actual words you use depend on the program using the .xml files.

I highly recommend reading this tutorial to understand what XML is and how it works. It's much simpler than learning to code actual programs, believe me. Once you've grasped that, editing .xml files should be easy.

Generally, you'd need to know XSL to make chapters, correct? At least if you want to edit MapWorldView and such...

Reminds me, I have an addin that Daft started working on and never finished that would make chapter addins not override the original game... I should really finish that up...

Really? I'd like to take a look at that, if I could. Sounds interesting.
Just saw the thread related to this, it's cool.

I just use David's XML Diff Tool. It works perfectly for me, so far I've had no problems. If you want to fine-tune stuff it might be handy to know XSL, but it's not really necessary. I have no clue how to use it and I've made successfully merging .xsl files.

riiight, thanks for reminding me about that tool. Should come in really handy with this addin.

Actually, David's tool created extra problems when I was merging the properties and resources xmls into the Earth of Goo demo. The reason why, was cause it was copying everything that was already there and adding it in again! So I had to use the tool, but only copy what was necessary... VERY tedious...

So now I've SAVED the files I do have from the demo, so I can know what to do to make the full version!

Ah, ok. Good call and thanks for the heads-up. I'll be sure to check for duplicates once I get that done.

Hmm.. I finally tried to merge the levels ad gt an error - no manifest found. What's that?

That means that you don't have an addin.xml file in your .goomod's root. Check this out to see what I mean.

I have no idea why! the addin.xml is always there!

Is it in the correct format? Try copy and pasting the contents in between <code> tags, maybe we can find a fault.

Strange, looks all right to me. I wouldn't know what the problem could be. Are you sure it's in the very root of your goomod?

Yes! I believe something is very wrong with my gootool! can you try the mod? if you want, ill post it in the "errors" level pack.

What the hell?! it does not post! INVALID MANIFEST! I NEED HELP!!!!!

No need to shout, we can hear you Unfortunately I can't see anything wrong with it, but maybe MOM or goomatz could find an error.

Is it named "addin.xml"? Are you sure?

That means the only thing i have to do is wait for MOM or goomatz or anyone else to find an error
Ok! ill be patient!

@ RedtheGreen Yes, addin.xml

At the first view I can't find anything wrong in the addin.xml. Maybe it's the "2" in the addin name. It's only a guess but worth a try.
Could you send me a copy of your goomod for further analysis?
goomatz (at) gmx . de