This game is one of the most awful I've played in a long time. It lacks any content to make you want to even play it further. Instead of providing some levels and then offering some options to pay, you are literally bombarded with useless crap and clutter to force you to pay money. Yeah, developer need to make money and I happily pay if a game catches my interest, but this is the wrong route. 1/5 not recommended at all.
I got frequent bugs where after using abilites the hp of the enemy went into the negative and my vikings wouldn't progress after killing the last enemy of the wave. I even stopped using abilities and it still bugged quite frequently, not allowing me to progress any further. I did the boss on rank 26 with 22 chieftains and 4 beer guys; with 8 islands still uncaptured. In the end it was quite an unpleasant experience because I had to restart 3/4 of all my attempts because of the bugs. Decent game if it wasn't for this bug.
I liked the game very much - although it isn't the most unique take on the tower defense genre the art is outstanding. It might be a bit on the easy side though; I got 3 stars in evey level except 3 on the first try, and the last level was the only one which I needed to do multiple times to get a working strategy.
 "Heroes of The Banner"){kind=icon}
 "Frozen Islands"){kind=icon}
 "Ancient Planet"){kind=icon}
 "no-one has to die."){kind=icon}