However, if that's how it occurred, I could see the problem. Castle Siege is a very highly tactical match flow control stage. The IC game plan is generally going to be use Uair to take the lead in the first section because it's hard to run away there. On section two with the lead, ICs can either abuse the statue platforms to make projectile camping difficult, or can elect to destroy the statues to create an FD like stage since the upper platforms are pretty far away. The third stage is like FD, with the added bonus of the tilts creating better IB frame traps.
However, if you lose the lead on area one (especially a stock lead), chasing on area two is a nightmare and area three is stallable as well.