CastleStorm took be by surprise. If you ever played Swords & Soldiers, Angry Birds and any other tower defense game - and enjoyed them - CastleStorm is the game for you.
What it basically comes down to if you haven't played any of those games is this:
You're the good guy, you own the castle on the left (or right, depending on the mission). Your opponent owns the other, opposite, castle. You both own a ballista that can shoot about 9 or so different ammo types.
The goal is usually to destroy the other castle. This can be done by shooting projectiles at it. Damage it enough and the physics will take over, destroying rooms in the process. These rooms are filled with troops, by the way. Destroy a room with a specific troop and your enemy can't summon those anymore.
Troops can be send to help destroy the castle gate, after which they can then steal the flag. Capturing and returning a flag also results in victory. You can also send your troops to just distract your enemy.
You also own a hero that can be spawned on the battlefield to slay the troops of your enemy. You can summon them for about 20 seconds; after that they disappear and you have to wait a certain amount of time before you can summon them again.
Missions have secondary objectives, keeping the missions fun and varied, while also giving them replayability.
Of course, a tower defense game isn't a tower defense game without upgrades. Thankfully, there are plenty of things to upgrade; projectiles, troops, heroes, spells, your castle, you name it.
The sounds are funny and the textures are beautifully sharp and detailed. It's a gorgeous looking game, in its own way, of course. You can't compare it to, let's say, Crysis (obviously). That would just be silly... ... ...
Like I said CastleStorm took me by surprise. It's been a long time since I had so much mindless fun with a game.