Slushline
Game
Slushline is a browser game seen from the side. A conveyor belt carries empty cups from left to right under a row of slush spouts, and each spout has a handle and one key: holding the key pulls the handle, the valve opens, and slush falls into whatever is below. Every cup carries an order naming its flavors and the share of the cup each one should fill. A cup passes each spout once, so the pour is metered as the cup goes by, and at the end of the belt a lid closes it and it is scored on how close it came to full and how close its flavors came to their shares. The orders get harder along a single path of missions: one flavor, then two in a cup, then unequal shares, then three, then blends that replace a single-flavor spout. Two players can each run a line, at one keyboard or between two browsers.
Everything that pours is simulated. Slush is made of units that fall, pile up with a slope, swell for a moment after leaving the spout, and spill over a rim. The handle is a lever rather than a switch, so a spout does not close the instant a key is released and slush already in the air still lands; judging that tail is the skill the first missions teach. The flavors are told apart by a motif, a brightness step and a hue from the Okabe-Ito palette, so that any two of the three can be lost and the cup still reads. Online matches run with no simulation server of ours, though connection setup can still involve external infrastructure, so that is not the same as no network services.
Checked in Chromium, Firefox and WebKit.