1) War galley requires zero record keeping. The movement is interactive, by squadron. This may technically be less realistic than sci-movement but it plays much faster. It also emphasizes good leadership (the admirals are rated for initiative) and a good admiral is more likely to win the initiative and have greater control of the battle. All the values (attack, defense, crew skill, marine strength, speed) is printed on the counter so there is nothing to look up.

2) the game is intelligently abstracted. In Trireme it was a long attrition process of holeing and crippling and boarding. War Galley uses a more black and white system. During a ram attempt a ship will be rammed or not. A Rammed ship is dead in the water but can grapple and board an adjacent ship and capture it. A boarding attempt either captures the ship or not. Marine losses are recorded with a marker on the ship. While some might prefer a little more tactical detail, the game does have modifiers for many things (towers, fire, artillery, etc). It plays quickly with little loss of realism compared to Trireme.

3) There are a few extra maneuvers allowed, the Diekplus Pass thru, the Anastrophe, quick 180 turns.

4) there is a much greater emphasis on command control. A good Admiral can control the battle batter and can contol a larger force. Once the lines meet all hell breaks loose anbd a good admiral can control more ships, farther away. rather than concentrating only on the tactical aspect of combat (Trireme) War Galley focuses on the grand tactical as well as the tactical. There are more ships but because play is fast the scenarios take 3-4 hours. There are losts ohigh level decisions to make like which formations/squadrons to commit and when. For example in Ecnomus as the Carthaginians I sent in my fast ships (light Triremes) and at the last moment did a 180 and pulled them back. The slower Roman ships were deployed against them, and not in position to deal with my 2 squadrons of Quinquerimes coming up on the other side. The scenario has 22 cathaginians vs 26 Romans. There are more ships and more strategy amd maneuvering.

There are more rules than in Trireme, but the game is quite simple once one gets thru them. Trireme may have shorter rules, but its not as good a simulation, and certainly not as good a game.