Much the same, which is definitely not a bad thing...
After having played through most of the game, however, it feels familiar - not identical. Even though the two games play at exactly the same timeframe and tell the story of pretty much the same characters, Earned in Blood is a lot more difficult to master.
The gameplay remains unchanged... as the leader of your squad, you get to order them to fall back, give suppressing fire, fall in line and follow you, or simply assault a group of enemies altogether. I prefer the suppress-and-flank method myself, but that's what's so great about this game. There's no one single way of doing things. The choice is yours!
All in all, I would definitely recommend this game to anyone who has played Road to Hill 30. If you haven't, then I highly recommend playing through it before even bothering with this much more challenging follow up.