It's not overly hard persé. It's mainly that in a lot of other missions, you can choose how you handle the situation, be it close range dogfighting, furying everyone to death, long range missiles, that sorta thing. A game of tag forces you to pull hit and run, which does not suit everyone. Combine this with the Ulysses, which focuses on dodging as the primary means of dealing with enemies as opposed to the stand up fighting Perseus and the heavy-weight brawler Hercules, and you really have got something that can push some people far, far away from their comfort zone.