TileMap Limitations

What are some of the technical limitations of the tilemap. I was making a game with 128x128 tile maps. How big of a layout can I make with this kind of tilemap?

It would be good to have limitations for layouts in the same way that 3D games have polygon limits. A pixel limit of tilemaps or layouts might be a good idea.

I can't think of any limitations with the tilemap at all. You should be able to use any size tilemap with any size tiles and it will work more or less the same.

That's really great. However is there a layout size restriction? Could I, in theory, my a huge one layout Metroidvania game?

There's no layout size restriction. Generally there aren't any hard-coded limits.