I ran across this yesterday and decided I’d give it a try. Several hours later, I forced myself to save and exit, or I would have ended up getting carpal tunnel syndrome in my eyes! GemCraft is one of those really simple games, but with totally addictive gameplay.

GemCraft

The idea is pretty simple. Beasties come out of one building and try and get to another building by travelling along the path. You have towers in which you can place gems. The gems will automatically shoot the beasties. You can combine gems to make more powerful weapons, in order to destroy more powerful beasties. After the first few levels, you can also create more towers, add water traps to slow the beasties down and more.

Check it out over at Kongregate.