First of all unlike the 2013 game it doesn't have a Linux version.
That prevents me from being able to say more about it.

I have played both and would say Shadow Warrior 2 is really good. I found the level design good, no glitches and the story is just silly fun that I made me laugh several times. Best part is the combat and has some cool weapons. It did feel a bit short and would have liked more NPC interaction.

As for comparing to the old one, hard to say, they feel like very different games. Shadow Warrior 2013 is linear which also makes it more story focused. There's a big difference in graphics, seem to have a different style but could also be that Shadow Warrior 2 looks more modern.

Was talking about this yesterday. Its a bit like trying to compare the original COD 2 games to those which came after. The first SW 2013, is fairly linear, has a great story (for a FPS), and has the action you would expect. The second has far more open levels, really big and almost totally open, however there is two styles of swamp and neon city, and its all just a randomisation of that. Which is bearable. There is no story. The action is high paced again, I found the annoying overuse of shaders and special effects to have appeared in this one which makes sword combat just a mess of colors on the screen. There is a weapon upgrade/character upgrade system that's way more complex than needed which meant it wasn't fun. So overall I would say 8/10 for SW2013, and drops to 5/10 for SW2, note I have completed the first 3 times now and the second once and have no interest in replaying the second.

I can only say that I like the original Shadow Warrior more than the 2013 version.
I cannot play Shadow Warrior 2 because there is no mac/linux version

I can't play it because there is no linux version... so why comment?! What is the point??? The never ending whinging of linux people, does it ever end?!

They are the vegans of gaming. It's never going to end.

I personally prefer the second game cause it's more open! The story is non-existent compared to the first game though, and that is a low. They complain everyone bashes linux users, but with them making comments like that on every thread they're simply asking for it.

Definitely SW1013. Better story, better settings, better end bosses, no random levels, no useless loot.

The second game is stupidly grindy with a pointless loot system and a boring open world.

SW 2013 feels like a proper, almost-old-school FPS.

Also see Totalbiscuit's review on Youtube, that sums it up very well.

The first one plays like the new DOOM, controlled and expected, you know whats going on where your going and how to do it. It holds your hand from minute one to hour 10.

The second one plays like Hellgate: London (the only game like it that exists) you exist in a hub over-world and adventures are randomly generated loosly around a theme quest... yes there is a story if you pay attention but most go all ADD and miss it. You need to work for ShadowWarrior 2 for it to make sense... its not going to hold your hand and point you to the next story element.