Dianyan Battery is one of Lushunkou's old coastal fortifications, built in the late Qing period with imported German cannons and later strengthened during the Russian occupation. It saw use during the fighting with Japan, which gives the site a harder edge than a simple viewpoint.
The battery is most interesting if you are following Dalian's military and treaty-port history. Expect earthworks, gun positions, and a coastal setting rather than a polished museum experience.