As per @Chowda 's recommend I downloaded the Dungeon Defenders demo off Steam. Rolled a Mage and went with all the defaults. Tried single player as I didn't want to be eviscerated as a noob.

The intro didnt say a ton about how things worked and over the first few waves I figured things out. Basically it's a first person tower defense game. Graphics are good and the play control in confused me a couple of times.

Survived well into the last wave when an Ogre spawned. I focused on the Ogre way too late and he killed the eternia crystal, which is what you are protecting so game over. Spawned in a tavern and the game explained what that was all about.

I like the art of the game and the tavern feels nice to hang out in. From the tavern you can meet with your group and head out to defend eternia crystals from bad guys. Saw no limit to the demo save one mode. I checked to see if anyone was online and didn't see anyone. I imagine the demo is on its own server.

It's a fun game. Knowing what I know now I believe I would focus on the Ogre sooner :)