GOW visually was impressive from the start for me. The turtle house area I found a bit of a wow moment, and the Lake of Nine area a little more so, then World Tree, and then when I passed the pillars in Alfheim, I leaned forward on the couch and just stared. It's not the last impressive area you'll see.
Early in the game you don't get a lot of gear and hacksilver isn't as plentiful. Eventually you will get to a point where you will definitely notice it ramps up a bit, and it tends to pick up from there. I found buying gear wasn't all that useful early on anyway. Upgrading weapons and skills was more useful.
As you level up the purple enemies will become yellow then green if you wait long enough. Yellow makes for good fights and green is pretty easy.
You can go back to most area's when you finish the story, but there are a few area's you can't and there are some transition points from area to area that are blocked off as well. I tried to get everything on my first pass through and didn't miss much. I did miss a gold chest in Thamur's Corpse, which I couldn't go back and get after, but luckily once you finish the story you can go to a shop and purchase that item.
I've finished the main story. I'm not quite finished overall but fairly close. You're not even half way. A quarter, possibly, maybe not even that far. Hard to say exactly. If you're going to do everything then there's plenty more. The story no doubt get's better and deeper as you go, and if you know Norse mythology, it makes it even better.
