Inexperienced middle management (and upper management as well...) - Inflated job titles for "managers" with minimal professional or industry experience was a nightmare. Results in few learning opportunities and poorly performing teams.
Highly unstructured in every way - You would think with all the funding there would be some business processes set up. I've seen 20 person companies with better infrastructures and processes. This is another byproduct of incompetent managers.
Limited engineering resources - Even with the company prioritizing engineers over everyone else things move excruciatingly slowly as engineers are too afraid of the tyrant CEO to innovate.
Interview process is a joke - Questions are often repeated across different interviewers and not focused on the role. As a result there are many unmotivated people that slack off.
Pay is well below market rate with no room for negotiations