It's a fairly robust tower defence, but a few niggles stopped me from continuing beyond eight hours. Firstly, gold accumulation is too slow to the point at which you can spend a minute or two doing nothing but placing the little pair of soldiers you can dump for blocking. Secondly, there are too many enemies early on to know their weaknesses. Add to this no rewind or fast forward and it becomes a grind. It feels like a mobile game. Otherwise, all fairly solid.