Direction shifts can come a little quicker at a start up than at a more seasoned company. This was expected going in for me.
This might be seen as a con to some so I'm putting it here too: we are currently a smaller company trying to do a lot, so there are needs, open roles, areas which can be improved but aren't making much traction because we're still growing and hiring. Because of this I'm able to expand my role to take on new challenges and add value (some call this wearing many hats). Will this last forever? No--but I personally don't mind it and I never have to work more than a typical work day. Plus if you believe in a company, a vision, a team, I think you want to help out in any way you can.