You do if you want to make your own levels. And yes, the Macintosh version doesn't come with JCS, nor do any Shareware Demo's. You, on the other hand should have it if you have full version 1.20 of higher. If you downloaded a full JJ2 game off the internet, chances are you got version 1.00g, the OEM version, which is a pre-release shipped with PC's, which doesn't come with JCS.

- JelZe GoldRabbit =:3