I remember at the very beginning of my first time through Dead Rising I had the same trouble but as I went on, I realized it was more of me just not knowing where the save points were. Once you learn the map, it's easy. Also I would say on your first play through the game, it's best to just go around and the mall and kill zombies and have fn exploring the environment and your abilities. FInd all types of weapons and level up. That way when you go through the game your second time, you have more life and attacks etc and it makes the boss battles easier.

I'd also say that I thought Dead Rising was an excellent game and I had a lot of fun going through it. I've played a lot of 360 games since then that I thought were mediocre (Crackdown, Call of Duty 3, Assassins Creed) so it might just make it look that much more appealing to me, but I'd say go ahead and finish it