Good but too tough for beginner

I've started Spark Fit Beginner from scratch but found this one particularly tough. I made it through the first too rounds okay but had to finish most of the other exercises in the other rounds 10 to 20 seconds early. All the exercises apart from crunches seem to concentrate on the fronts of the shoulders. I wonder if these exercises could be mixed up a little so as not to concentrate so much here. Just finished and the fronts of my shoulders feel very tight and sore.