
Well, yes, I've just completed the game "
The Land Before Time: Big Water Adventure" for PS1, and now I'm writing this review with the fresh impressions.
CAUTION: SPOILERS! 
This game is more difficult than
Return to the Great Valley, but, unfortunately, less interesting.

I've spent about 6 or 7 hours to pass it completely.
Why "less interesting"? Because it has 56 levels, but the actual amount of levels is 14. You have to pass the same 14 levels playing as different characters - Littlefoot, Ducky, Cera, Spike. There are no any difference in levels: level structure is the same, collectable items are on the same places, characters don't have any special abilities and have the same parameters (what about Ducky who can push the big stone which is 10 times larger than her). Every character has the same actions. The difference is only in some cutscenes between level groups. Yeah, these 14 levels are divided to 4 groups (The New Water, The Great Landbreak, The Soggy Swamp and The Mountain Pass). The cutscenes between the groups show why your current character has to escort Mo to the Big Water only with Petrie, without others(spoiler: different events which isolate the character from the Gang). Petrie is unplayable, he just gives tips.

What about the game mechanics? They are very boring. There are no enemies (except of one useless sharptooth, which can't harm you and defeated from one punch); no health/life system (so you can fall to the bottom as much as you want), and you need to collect 30 treestars on every level (420 total). The treestars are collected separatedly by every character (so, the maximum amount is 1680

). Yes, some levels have quite complex places where it is quite hard to reach a treestar, but usually I passed the level less than 2-3 minutes. Sometimes a level can be loaded longer than I play it!
Also 3 of 14 levels are "racing" where you have to reach the end of level faster than other dinosaur.
Even though the game has 3D-graphics, you are playing it in 2D (only left and right direction are available).
Every character has only 3 actions - jump, attack (to fall trees to make bridges, push out the rocks and knock down treestars from some trees) and "say hi to Mo". If you press some buttons, your character says "Hi Mo!" and Mo jumps out of water.

Quite funny, but it is necessary to get treestars from water where you can't go. If you are playing as Spike and trigger this action, Petrie says "Mo, Spike says hi!"
Petrie and Mo are playable in their own minigames. While you collecting treestars, Petrie unlocks puzzle images in his minigame. There are 27 images (screencaps from LBT9 in quite low quality), every image is divided to 9 pieces (3x3) and you are controlling Petrie to solve the puzzle (in 2D again). Every puzzle I've solved for about 1 minute.
Mo's minigame is unlocked when you pass the game
4 times as every playable character. And it is quite short, there are only one level, you need to control Mo while he is swimming automatically (you can move him left/right and change his speed) and you should jump in 30 rings. If you do it, it will unlock the secret cutscene. Quite funny when Mo gets into a whirlpool - the control buttons are reversed (left button moves him to right and etc). But I spent only 10 minutes to complete his only level.
Other notes:
Strange thing: I didn't hear the background music, even though it was turned on in the game settings.
The graphics worse than in the
"Return to the Great Valley" even though it was released later. Look at this Ducky in the beginning.
Or at this Spike under drugs.

But they used different 3D-models for cutscenes and they look pretty nice.
I'll do the comparative table between the characters from both games (3D playable model and 3D model from cutscene). I think it will be funny.

Well, summarizing the above, this game has only one advantage - it is about LBT. But I wouldn't play it again.
I wonder why developers didn't use the concept from
"Bugs Bunny and Taz: Time Busters" (which was released that years). There you can control 2 characters at the same time by switching control, and both have totally different abilities which you have to combine to go through. I think the LBT game with the same concept would be MASTERPIECE
