I liked the previous game's art style more. It created more of an atmosphere fitting for a murder mystery. The creepiness of the art style was just so much more fitting.
Here's a tip for the ban hammer mission: Never fight them in a group, kill them one at a time. Grab the Health packs in the bottom center of the map and armor at the top center of the map. As for second to last mission, if you seriously have issues with it, just play a sniper and stay out of their aggro range.
While I do enjoy that this game allows better customization, the enemy AI feels like a heavy downgrade compared to the first game. Also I wished that you could play the maps from the first game in the custom games list.