Steve confirmed that it is a whole new track, just using some assets for the graphics, but the layout is 100% new.
The returning tracks will be the same layout, but probably with flight and boating segments added.
The reason Seaside Hill is new, and returns in the sense that we saw Heroes repped in the last game, is that early in Transformed's development this was the test track. Since Sumo had the assets, they used Seaside Hill as the setting for testing the ground/air/water mechanic. The track ended up being decent, but nowhere near as good as the tracks being developed for the game as proper non-test tracks. So they had the choice of either scrapping it and leaving it as behind the scenes only track, or putting the effort in to improving it and making it a proper track. So they went with the latter and made it a track found in the game.
