From the cover it's obvious that this album has been made with a twinkle or two in the authors' eyes. Don't let it fool you, this album is still solid rock. Singing may not always be on the same level with music, but at least it's not irritating.
There are deviations between styles, namely from older rock to very modern "crash-boom-crash" kind. The basic style is still recognisable. If the singer had focused more on music and less on torturing his vocal chords, this could have been quite a piece of work. Now it's just a decent curiosity and somewhat mediocre rock.
But rock is still rock.