ES1? You mean EP1?
Depends really, it is a very short game, around 4-5 hours +/- an hour.
It's best you complete Half-Life 2 to be honest before you do play Episode One, as it follows on directly from Half-Life 2. It's pretty pointless if you havn't completed Half-Life 2 in my opinion, as you're only going to like Episode One if you enjoy Half-Life 2.
There are no car / boat vehicle bits in it, but it does have a concentration of the best elements from Half-Life 2.
If you've got £13 spare that you don't mind parting with, go for it.