At least it ain't on rails like the Time Crisis Series. Tell me what's better!!!
In Dino Stalker, the environment often goes slightly linier but there is always a little bit to explore along edges. Plus the load time is pretty long. The environment suffers from minor pixilation a PS2 standard problem for most games. The AI and character animation is lacking but doesn't completely draw the game down. The CGI of the cut-scenes seems to be close to cutting edge for it's time.
One problem aspect of the game centers around the edges of plants and other objects which will take a shot outside of it's visible area like when a Dinosaur is partially obscured by an object.
One of the best part is... like MERCENARIES and MECHASSAULT much of the environments are completely destructible. Really cool. You can take down a tree... roots and all... with a grenade or powerful firearm.