Edit for current pricing: 14.95 EUR / $20.51 USD
At first, it doesn't seem that interesting.... until you get attacked and need to find a way to fight back... OR - if you have admin controls and want to build some crazy lego style building/trap/mine/etc.. Of course, you don't have to have admin to do that, you just have to locate the resources needed, do a lot of crafting, and piece it all together.
Ya, I'm getting pretty hooked.......