It was a good try but they tried too hard
The Good: The tracks were designed very nicely, good difficulty level and a wide range of tracks, bikes and bike tuning.
The bad: Over realistic (They tried too hard with this. You turn a bit in the air and land like that and crash), No track editor, Iffy graphics and it basiccly was releaced at a difficult time as there was many Motocross games at the time.
Overall I think that this is a good game to buy cheaply but there are many other better cheap PS1 games on the market.
Instead of this you could get: Championship Motocross
Championship Motocross 2001