A game that, on the surface, seems to have everything together.
Let me explain. When you start the game you're given the choice between a Mage, a Knight, an Archer, and a Monk. Oddly the characters are given a difficultly rating, with the Mage and Knight being considered easy classes, the archer is medium, and the Monk is Hard. What this translates to is that the knight and mage have useful towers and the Archer and Monk do not. Remember this game is large part tower defense. What this translates to is a game that can be completed solo as one of the easier classes, and can not be completed solo with the other classes.
Not only that, but each class has different attacks. Everyone has a primary attack and a secondary attack. The main attack of the mage is blast that can be charged for additional damage and AoE. This attack never needs recharging. His secondary attack is a useful radial attack that pushes back all enemies around him. Sounds cool right? It is. Meanwhile, the archers main attack is their weapon, and their secondary attack is... reload. Seriously WTF?
This imbalance is further exacerbated by the multiplayer focus. One would think that a game with 4 playable character types and a 4 player co-operative campaign would be most enjoyable with 4 players, one of each class. Its not. What a 4 player match ALWAYS becomes is one mage or a night setting up the primary defense and everyone else doing whatever, usually just getting in the way. Since the enemies increase in number and health based on the players, this further renders anyone who dare play the Monk class useless.
Of course, this is just in the main campaign. There are many Challenges in addition. These, however, usually place further restrictions rendering some classes even more useless. At least two challenges limit the range of the ranger's ranged attack. This same challenge also inhibits the use of towers and hero powers. This makes that class essentially useless in the challenge and is basically a huge glowing neon sign, placed in the game by the developers, telling the player, "You need to level your Monk Class!". Oh, ok... lets see, what level does my monk need to be? Oh... 60? Well, where am I supposed to level him? Oh, in the campaign... where he is useless. Wonderful....
There are just so many things in this game that scream "bad design". Its even more disappointing for me because conceptually, I love this game. The problem is that it intentionally reduces itself to a grind and lets loot drops and compulsive leveling be its only thrill. If the game was balanced more and had a tighter focus on strategy, over just plain leveling, then it would be an inspiring gem. Its innovative, but, right now, its rough. Eventually, the developers might polish it until it shines, but I'm not waiting. At that point, someone else will have made something better. Basically, this game is not worth your time.