That's the river one right? That's perhaps my favourite level in the entire game. Between the darkness, the endless Laguz assault, and the water slowing your movement speed you're on a knife's edge the whole time. However, if you've trained the right people (Micaiah, Sothe, Nolan, Aran, Jill, and Zihark) then you shouldn't tip over that edge. It's also the moment when if you try to train a decent number of the Dawn Brigade, you're really going to start feeling the pain. The easiest time I had with it was training the aforementioned six minus Aran, but I felt like I had enough experience going to waste towards the end of part 1 that I could have trained another unit, and after taking a look at the Dawn Brigade roster I think Aran's the best one of the remaining characters. Plus it gives you a nice on foot weapon triangle core with Nolan, Aran, and Zihark.