Innovative, pretty, decent length for a platformer, but dreadful collision detection and cheap deaths hold it back.
The gameplay is somewhat similar to the first Jurassic Park on the Genesis, but a little slower-paced and the platforming challenge seems simplified somewhat. This is probably because the collision detection is ATROCIOUS! It's not as noticeable playing as the Human Hunter/Sarah (because they have guns) or T-rex (just because he's huge), but the compy levels feel like a chore that needs to be completed to reach the good parts. You have to get a feel for the collision boxes on enemies so you know whether you're going to bite them or fall short and expose yourself to attack. Controls could also be much more responsive, and again this shines through the most on the compy levels just because he's such a tiny little guy.
Cheap deaths are also a big problem. Some of the characters have the camera situated way too close and leaps of faith are far too common. Parts like in the compy levels where you have to get past the sauropod legs, while very cool, also result in way too many unavoidable crushings. The difficulty of the game just seems a little unbalanced. Not too hard, but just... cheap.
It's a shame that these aspects are so off because the rest of The Lost World is really really well put together. With a little extra polish this could've been an excellent game. Everything looks really good in the background and up front. The character animations are really charming. Environments from dark rocky caves to lush jungles all look... well, like dark rocky caves and lush jungles. The sound is also awesome, the BGM could've come straight out of the movie and dinosaur shrieks and growls really pop out and grab you.
The best thing about the Lost World is that it feels like four games in one thanks to all the different characters (Sarah and the Hunter are basically the same gameplay style). Once you get to the end of a playable character's run, they fight the next character and then you take control of him/her. It's exciting to start out as a pathetic compy and move your way up to the majestic T-rex, gobbling up humans left and right.
If you're a fan of Jurassic Park, I'd say run out and get this right away. If not, you might want to think twice, but you never know, you might get a few thrills.