Does the client slow down computer

No it doesn't. But the client is very slow so expect framerate from 15 - 30 fps while playing brick hill.

Thanks mate i was Pretty worried about my PC,glad that there is helpers in this community

The client is very slow, there working on a new one (and im working on improving the current one)! they used something called GM8 to make it which is for 2d games not 3d games so it struggles to load 2000 bricks on most pc's!!