Tips for spearmen: Choose one small spot on the lane to break through. Put most of your spearmen there, and just a small amount on the rest of the board (enough to keep the enemies at bay). The you use the big group's special attack (all of them charge) to break through with lots of spearmen at the small spot while you use your bombs to get rid of any enemies in the way. When you upgrade them, spend the points on push or defense.
After several tries, I finally managed to win the game on deity mode. 3 Ice ages, savages attacking at every turn at the end, next to no positive events through the whole game, and ending with 3906 rating. But I won!
I'm sure I speak for all of us when I say that it would be nice to be able to sort the weapon types. It is nice that they are already sorted by level requirements, but it makes the inventory messier and makes us have to look longer to find a specific weapon type.