I wont go on about three new games to compare for the different genre question. So pac man is a big maze where you go around eating things but you don't want to get eaten by something else. Very simple the reward is points and the next level and the risk is death and the level is design the way it is so that the player can trap themselves if they are not careful. sonic i have already told how the levels are very linear for speed sake and like pac man the reward is the next level and the risk is death. halo is much the same like most games are much the same the reward is the next level and the risk is death and there are just little variations on that in general. The games genre changes the level design in the sense of what it is a shooter needs cover a side scroller needs platforms and so on.