First thing is that I enjoyed the first Helldivers even though it wasn't great as a single player game.
This is the potentially much better in my early play. Better visibility around the playing area (the difference between 3rd and top down view) allows more freedom of the squad. Missions are larger.
I played first few mission solo. How I love the weapons.
Better use of the environment to find advantage ( elevation, cover etc) . Some server issues on day one (expected) and once things settle down I can see players sinking heaps of hours into this.
Great price.