A game of 40K

It's been a while, but I finally managed to squeeze in a game, around at the dungeon. I wanted to give 40K another try - I have played it a few times and never quite seen the appeal, but with such a huge player base I reckon there must be something there right? I have a small Dark Angels force which was pitted against Matt's Tau. We rolled up a scenario from the battles book, but it turned out