I agree with most of the ideas being said on this thread concerning DT music, the previous albums in contrast to the latest ones. Here's how I see it:
Music and poetry (songwriting) reflect the state of mind of the artist, and this state of mind is constantly changing, being affected by age, experience, and the general world state of mind.
Dark Tanquillity have evolved through the years from sounding raw (tr00) powerful, romantic (like a teenager dreaming and expressing his feelings in the most direct way).
Skydancer, Chaos, Gallery: raw anger / romantic.
Mind's I: is more experienced still very raw but goes darker, also romantic.
Projector: is depressed, sad, as if disappointed in many things about life...
Haven: is an extention of projector, anger is subdued and sadness still dominant..
Damage Done: is a continuation of the Mind's I, same raw dark dominant anger and rage, it is as if the artist/s here is rebelling against his own state of being, now that he is more aware of what angers him. It is also romantic.
Character: reflects today's world which is lacking magic and a dream. It is very detached, too deep and too personal it stopped even being personal at one point. The message and feeling are buried way deep that it is going to take the average listener a much longer time to appreciate (in comparison to the easier to understand Gallery).
Fiction: follows Character in the same line of thought but the musical structure is easier to decipher and relate to.
If you think of these albums as each a painting, then each one comes with a different color and mood. Don't forget that this band is singing about the times we live in and what effects our world has on us as individuals. We start off as dreamers wanting to conquer the world and suddenly we realize that we are so small, insignificant and vulnerable, our thinking changes and so does our ways of expressing it.
Someone mentioned earlier that there is a drop of creativity in DT's work, I think not: it is only a different mood of expression that's all. In psychology it is said that a human being goes through 4 stages when faced with something he/she doesn't like: Denial, Anger, Acceptance, Resignation. I think DT's work goes progressively from one state to another.
Technical differences: Artists like to exploit and take advantage of technical progress. What new sounds can be used, what new technology offers, not to mention the artists' growing abilities. DT have become very sophisticated in their music, the melodies and ideas, even the structure of the music is way more complex now that what we are used to in their previous work.
Remember how much time it took for us to get our ears tuned to early death metal? After 3 years I have finally started to appreciate Character, its technically artistic composition, its highly polished sound... Music is like wine, it takes time to sink in and be fully appreciated.
When you want anger you listen to the Gallery, and when you are in a state of apathy, Character brings you down even more, when you are feeling melancholy Projector fits the mood.
Character simply lacks character, it is impersonal, too objective, everything about it sounds machine made. It is precisely a state of apathy, lack of romance and magic. Fiction has more romance in it and is a little more human.