Run Space Marine run! All levels have a timed component. Make your way decimating the Greenskin scum as fast as you can to get the best score and the most stars - for the Emperor!
Block is a powerful tool. By holding block you can absorb enemy damage, but keep your eye on the blue bar which shows you how much damage you can take before the block breaks. Some Wargear can improve your block stats, look for Wargear with the “block” modifier.
Without a Jump Pack your Space Marine can jump a considerable height but to get to the upper platforms or out of a deep well equip a Jump Pack from your character wargear/equip page. Then hold the jump button to engage the Jump Pack for additional height.