I just played it for around 1,5h and I'm definitely not done here. First impressions:
I don't think trying to tackle any of the lengthy, multi-objective missions solo is a good idea with hordes the game throws at you, big and small in the mix.
Felt surprisingly hard at times this way, I managed to get halfway with the rifle/shotgun chick and failed.
That's because there is a respawn limit, 3 times dead and it's back to the main menu. There is a self-revive mechanic when you're downed but then seems like you need someone to pull the aggro or you're screwed...
Dinos are fast and surprisingly good at maneuvering the environment and you're constantly chased, ganked and have to push back... but it all kind of works together as a really decent first-person shooter.
Gonna try matchmaking next time, should be really fun in PvE as intended.