In Jak 3, during the battle for Haven City, the Palace was destroyed by Count Veger destroying most of Main Town. Other parts of the Town are all beat, swarming with Metal Heads, and is accessible. Jak can go through the ruins of Main Town with the Slam Dozer and some parts are familiar. Including beat up billboards, bridges connecting street to street, and little water.
The Main Town was once the most beautiful area in Haven City and showed its potential, with beautiful buildings and bustling streets. There were numerous small canals going through the entire area and could be traversed by zoomer.
Unfortunately, during the beginning of the war for Haven, the Palace was destroyed by Count Veger and fell on top of Main Town, leaving it in ruins. Main Town's position as the main part of the city was taken by New Haven, but was rebuilt in Jak X: Combat Racing.
During the race against Erol through the city in Jak II (Beat Erol in race challenge) it is possible to see a Ratchet & Clank poster over one of the canals. This poster is visible at all times in Main Town, but is easier to spot from the race route.
In Jak 2, after beating the main game, the number of Flying Zoomers spawning in the Main Town greatly increased.