20-25 hours? Doesn't sound like a good tutorial. I think you should be able to learn the basics of a game in less than an hour before moving on to playing the real deal.
It's not the place of a tutorial to introduce every single unit, tech, race, building and spell in the game. Just the basic concepts please, leave the rest to discovery.
It's not a true tutorial in a way. It's a true fully fleshed out campaign that goes across 8 chapters and includes things as some peaceful city building and quests to massive island invasion and naval battles. The tutorial part is that your main ally for the chapter will prompt you to build certain things if you aren't already. Like you need glass to build a cathedral or something, your ally will prompt you to build the factories and resources in the production chain to make glass. Thus it also acts as a tutorial. And after all that It probably only covered half of what is available to you. It is a pretty massive game.
Quests themselves also act as sort of a tutorial. So for example an ally may request you to build 3 large warships for them in trade. Ok, so how exactly do I get the materials together to build these warships? If you spend too much time your ally will give you hints on what factories or building to build to get those materials. So it acts as a tutorial in a way.
It's very hard to explain because it's not an explicit tutorial like is included in say Sins. It's craftly (in my mind) integrated right into the game play of the campaign and senarios.
If I played the campaign again I could probably finish in 10 hours or so if I rushed it. But there is no manual for this game and I had no idea what I was doing at first. After the first 2 chapters I had the UI down and I just took my time exploring all my options, even those not needed to finish the chapter. Also remember this is a city builder/RTS type game so with some things you just have to wait to build things until enough resources come in.
Currently I'm playing one of the easy level senarios which is simply to accumulate 150,000 gold, 5000 population with 2000 of them being nobles. My "benefactor" is there and still offers hints from time to time. But with each hint you gain various achievements, honor (with which you can buy things) and so forth so it's nice.
So there are 3 "modes" for this game:
1) Campaign. The main story behind what's going on. 8 chapters and can be played at various difficulty levels. You get hints from your allies so it acts as sort of a tutorial.
2) Senarios. There are 6 senarios of various difficulty. Basically they are open ended games with a specific goal in mind.
3) Continous Turn. This is where there is no goal. Very much like Sim City games or Tropico. You're just building up your city.