Yep, especially if you spawn a ton of chains--all the physics objects trying to interact with each other every tick chugs it bad, even in the standalone, so probably more so for the web player. Unfortunately I don't know why it would take a long time to load, though.
Sorry it didn't work out! A couple problems I needed to fix if I'd had more time were the buggy UI buttons and making the piston cylinder look more like you needed to put a piston in there. Glad you had some fun. :p