So I ran through this out of curiosity, and all I can say is that I hope it isn't meant to be serious. All of those phys/breakable objects you added do nothing but interrupt the flow of the first section of the map. You can even get stuck in them. The explosive barrel could easily be used to spawncamp, the elevator platforms carry you up to the skybox and drop you for some nasty fall damage, and that tank just blocks the cart and takes extra effort to destroy.
It's good that you're experimenting with the Source engine, and using a Valve map as your sandbox is fine. But it's not something you should release as a serious map.