Spires miss an agile target with the first shot, get in the second shot, and by then you're under the lung.
G66 cheats...

As said, you'll find different setups depending on what settings you choose, and the whole point is to keep you limited in your wanderings until you advance enough to handle moving into that area. Greenheart maps use the giant statues to do the same thing.
The whole idea of IA is to learn different techniques, come up with different strategies, and learn to handle more powerful enemies.
-Av-