I almost never rate games, I've only ever commented twice, and I've never favorited. You, sir, have earned all three. This is a really, really, really great game. If I had a shiny gold medal/cookie I would give it to you. K bye.
This is the best online "monster capture" game I've ever played by far. The only thing I would add is some way to pick and/or change the +5% attribute for your minions. An interesting idea might be to have separate capture missions, instead of getting a random monster at the end of every level. Depending on the mission you select, the minion's main stat could be determined. (Escort +5% healing, battle +5% attack, etc.) Kind of like the selection option for the starter minions, but a playable 'backstory' for all of them. Obviously that's too much work for an update or anything, but maybe in a sequel, which I'd really love to see.
All blue deck with max of every blue creature and hive mind, which is optional, is pretty much unbeatable. By that I mean I have literally never lost with it except once during the "On The Brink" challenge.
Story has huge potential but isn't utilizing it. I was super exited when I saw the continent map, because I thought that there would be a great story and lots of levels. Instead, there were only 3 battles per continent. Units spawn way too quick, and enemies don't send waves. Also, this needs a castle to protect. The hero death thing is a little weird. It could still work, just the game would be better with a castle. I really like the leveling system where each unit gets their own special level bonuses. However, I think leveling should go back to gold and have more upgrades available. Each unit receiving its own exp is like the hero death; it could work, but it would be better without. One last thing: the game's pace I think is too fast. I know that's VERY subjective because some people like faster games, but the EW series is a strategy thing.