Its just a natural progression of the gameplay. The first game in this trilogy was more linear, with just arenas to fight in and then move to the next. Much in the same vein as Painkiller games. The second tried semi open world with a hub area and for many it didn't quite gel well and became repetitive as you had to back track alot. Now this game moves back to the more linear level based routes but it has to evolve upon it and not just be another arena shooter with a quirky story line and characters. Sure this is obviously heavily influenced by other games like Doom but who cares it just adds more depth to the game and they seem to be taking what worked in those games and using it to the games benefit. I for one can't wait to see more of this game and shall be purchasing it day one.
