- Game control:
Portal is a puzzle game and the game, and this game instruction is from www.t45ol.com. The objective of each level is to open the gate and advance to the next levels. To do that you have to fill the energy bar in the upper side of the screen. Each stone disk rotation produces energy. The disks will activate themselves if the energy lines connecting. Click on any disks and try to produce a energy chain as long as possible.