Dungeon Defenders is a great take on the tower defense genre, I really enjoy playing it. I bought it on iPod (And it was a terrible experience all over) and waited maybe one year then I bought it on Xbox360 (Split-Screen Coop is not great and the griefing options were many) then on PC with all of my friends. Dungeon Defenders mixes action-rpg with loot mechanics and tower defense systems to create a nifty little game with some flaws that I'm going to look at in the following article.
A side word on DLC...
I haven't played any of it. There are about 6 new classes and about twenty levels and new modes in the game that get added by buying more things. I'm not a big fan of buying content for a game post-launch so it's not a point against Dungeon Defenders, however the way it's presented could be more elegant. When you boot up the game, you get two screens of DLC and "BUY NOW" buttons, when you get to the character select screen, all the extra content is shown but if you want to access any of it, it pops out a store page. I know you want me to buy your game, but if I haven't played since about a year and I see a new "Nightmare" difficulty added after "Insane" and want to try it, I expect it to work, not tell me that I have to buy that feature that appears right there as if it was unlocked. I know, minor gripe with the way publicity works.
How I would fix it
Make everything dlc-related clearly shown as such. Add a red overlay over the things you can't use before you pay, add a symbol, make the text another color, make a separate menu to buy these things and don't show them in the main game where I think I own that content.
All classes aren't created equal
The four available classes at launch were the Squire, Apprentice, Huntress and Monk. If you plan to play alone, do not go with archer or monk, you won't be able to progress in the game at all. This is because the Squire and Apprentice can summon towers that will prevent enemies from reaching directly your crystal (You must protect a crystal in each level against waves of enemies), Monk and Huntress cannot. The monk has auras with various effects such as slowing down enemies and killing them in some fashion and huntress can lay down explosives but they won't be as effective as barricades and barriers that can be put up by the squire and apprentice.
If you're playing with friends, a monk or a huntress can be a good addition to the team if they don't plan to use their traps, for balance reasons all defenses cost a certain number of points and they are shared amongst player. You can also specialize your character in different ways such as making your towers better or your regular weapon attacks better. If a monk or a huntress leveled up their attack and speed, it only makes sense that another played would put the towers up while you focus on killing enemies. It's kinda frustrating if you want to level-up a monk or huntress tho. You can always switch to another character so you put towers with your squire and then switch to your monk... But that will create another problem, as I will explain in the next point, so it's out of the question for me. Why make two classes that can't reasonably solo the game well?
Even then, the Squire is way better at putting towers up than the Apprentice is. The apprentice's towers have elemental attributes (fire and electricity) which means that some of your towers will deal 0 damage to any fire or electricity attuned enemy, which means that you'll have to put more than one tower even if it's strong enough to take care of the enemies. Squire towers are great, they cover any situations and they deal full damage to all enemy types, one could say that the mage towers have more diverse powers but that's not exactly right, the chain lighting tower and the harpoon tower have similar usages, idem for the bowling ball tower and the fireball one.
How I would fix this
Add one tower that blocks enemy movement and one tower that shoots ranged projectiles for all classes and that solves pretty much everything, now you can solo the whole game with any characters and you can still have the weird auras or explosives for the Monk and Huntress. For elemental towers, maybe lower their base damage, make it so elemental attacks deal more damage to opposite enemy types - make it a rock-paper-scissor system - but not 0 damage to enemies of the same time. Maybe half, maybe full, but having a part of your arsenal doing nothing against random enemies is frustrating, so that has to be fixed.
The game feels too slow
Between enemy waves you will have time to go around the map, open chests, pick up mana crystals and build towers. If the characters moved fast enough, if the maps were small enough, if the chests and defensible positions where nearby enough, this wouldn't be a problem. The maps get bigger, the chests are placed at very far positions and if you didn't put any points in movement speed - which you shouldn't if you want good towers or good weapon damage/health - you're going to break down the action pretty hard between enemy waves because you'll slug along the map trying to go and gather resources, place towers, upgrade towers, etc. Especially when you're playing alone, this becomes a problem in that it ruins momentum.
While you're fighting, moving around to tackle enemies and collect mana to upgrade your towers is fine because you already move around to kill enemies but when there's nothing else to do except walk around some huge maps doing nothing, you're not having fun. After playing all of Orcs Must Die 2, I noticed that while that game had some flaws, the action seemed more fast-paced because you didn't have to walk all over the maps to collect things between waves - also the timer between waves was close to 10 seconds, not 70 like in Dungeon Defenders.
How I would fix this
Stop putting chests randomly on the map, just make them closer to the things you're supposed to protect. Or award the mana automatically. Or just give a tactical view between waves when you're building so you can build anywhere you want on the map. Why would you physically need to move your character to a spot so you can build a tower? I understand why you would do that in the battle phase, but during the peaceful building phase? You should be able to just place your towers with the mouse and just get your mana and items that way.
I really like the stats/item system
Dungeon Defender is part tower defense, part action-rpg. The loot game is neatly implemented, you gain items from defeating enemies or in chests, some special challenges also give you unique things and you can buy them in stores. You also can upgrade your items with mana, choosing what stat to level along the way. That leads to really powerful customized items with the stats you want to fit your play style. Personally I like the magic staves that shoot multiple projectiles. You also have familiars with different abilities such as killing enemies or boosting your towers in different ways. That whole part of dungeon defenders is great - except when you get to the endgame where you need insane amounts of mana to upgrade anything, but I won't hold it against the game. I know how I feel about stat points allocation but since this game is about towers and defending spots, it doesn't matter too much how you spec your character. I like how different classes have different stats such as the huntress being able to upgrade how many times her traps will explode.
Another little thing they added since I started playing is "Pro Mode", basically it makes leveling-up your items faster. A nice idea over the regular "You have to fill up the mana bar before you can put your points" system.
Tons of content, even if it could be displayed some other way
The campaign spans over 15-something missions, you get about the same number of challenges (special missions with very specific conditions such as being unable to build any towers or goblins raining down on you) and there are four difficulty settings to complete them. You could play Dungeon Defenders for a while, but I wish they'd surface the data better. It says you need to be level 40 to do such or such challenge, is it on Normal difficulty? How about on Insane? What kind of level would I need? Why is the interface for the level selection kinda bad and too busy like that? I'm sure there are better ways to display the same information while showing more of it in a clearer way. (Also like I said in the first point, don't show me all that stuff I won't be able to play, thanks.)