Everything. Subpar animation, the voice actors almost audibly groaning from being in it and... By far the worst introduction to a series I have seen thus far. Just to give you an idea: Episode 0, the very first one everyone got smacked with? Adopted a side-story that you are supposed to read after the first (preferably second) route. Which is two hours long, a bit shorter.
Into 24 minutes. Along with the prologue which is 45+ minutes as well. Which was only shown at the very end with an extremely abrupt time skip and said prologue being done in a minute or two. Not even five minutes was spent on it.
There is more but yeah. Everyone was confused as hell by it because Episode 0 basically shoves random characters in your face with no context and weird pacing.