Even if that's the case, they can't shoot through the houses and it takes them a lot of squares to get through.
1. Don't always kill a weakened opponent if it's right in front of you. All this does is let a new opponent take that weakened one's spot.
2. Try to minimize the number of squares you're getting pounded on. Two is the MAXIMUM number of enemies you can take damage from, because if you're surrounded by three they attack twice for every 1 turn of yours.
3. Break up your opponents; if they're near each other they go faster.