I've found several anomalies while comparing the TFS files to what is displayed in game.
It makes me think that the TFS files aren't even used by the game, which is ridiculous because they take up most of the disc space. I'm sure there must be a reason for everything.
I'll try to explain the strange things I've noticed...
Firstly, for the map MAYO10.TFS, I open it in my map editor and this is the exported image, which is fine:http://i.imgur.com/lLkX1.png
The TFS file doesn't contain enough blocks to fill the whole image so we are left with some large empty areas. In the game, we don't see these:http://i.imgur.com/1PkHx.pnghttp://i.imgur.com/jPBDI.png
As you can see, the area is filled in with a similar colour to the water, but... the right corner in the last image only slightly cuts into the waves. On the exported image, the missing block cuts into the waves much more.
Secondly, for the map TROP03.TFS, the exported image is:http://i.imgur.com/BGFo4.png
It is also missing some blocks, and we can see that one of these is missing in game on this screenshot (bottom right corner):http://i.imgur.com/lzF9m.png
But strangely enough, another one of the missing blocks has actually been filled with an image in game (top right corner):http://i.imgur.com/0Cqvm.png
Finally, I tried to modify one of the TFS files to see if the changes would appear in game. I modified MAYO01.TFS to move the first block onto a new row at the bottom, and to colour in some pixels at the top of that block. This is how it looked after I modified it:
But in game, it seems like nothing has changed:
EDIT: I coloured in more pixels and I could see the changed pixels in game now (it was cut off by the camera before). But the block is still in it's usual place and not where I moved it to. I think the position of blocks might be loaded by the MAP file and ignored in the TFS file maybe? The MAP files might also contain some collision data, camera bounds data and animation data (like the flashing direction screens). I will investigate.
New Modified MAYO01.TFS: http://i.imgur.com/rFUJ1.png
In Game: http://i.imgur.com/OMpyi.png
EDIT2: I decided to remove the first block from the TFS file and place it right at the end of the file. This was to see if the block positions in the TFS files are ignored and the MAP files (I guess) have a position for each block. I was right.
What it should look like: http://i.imgur.com/TbHGE.jpg
What it looks like in game: http://i.imgur.com/6tMoW.png
Also in the 2nd image, notice how there is a toilet image overlayed on top of the map. This explains why we can walk behind the leaves. I guess this toilet image is also inside the MAP file and placed on top of everything. Maybe the missing block (which appears in game) from TROP03.TFS is also stored in the TROP03.MAP file.
So in summary:
MAYO10 is somehow filling in a missing section of the map with blue (but the missing section looks different in game).
TROP03 is getting a 128x128 block from somewhere other than the TFS file.
Modifying the file MAYO01.TFS seems to make no difference in game. I checked that it correctly modified the IMG file.
EDIT: Modifying the file MAYO01.TFS to move a block position seems to make no difference in game.
EDIT2: The map size and location of each block in the TFS file is ignored by the game engine. These values must be stored in the MAP files.
I will keep working on the map editor and I'm going to try and figure out the MAP files.
EDIT3: I discovered that you can modify the map and still load your old saved games fine. I've applied the same block shift technique to MAYO10.TFS and discovered that the missing block areas on the TFS file are filled in by another image (presumably from the MAP file). This explains the first problem above: http://i.imgur.com/84R1Y.png
I also noticed that the animations were overlayed on top (for the waves and the vending machine) and the computer item. They will probably be in MAP file as well: http://i.imgur.com/gQDxl.png
I guess I will also find the same thing for that mystery block in TROP03.TFS when I shift the blocks in that.
I guess all problems are now solved, which makes this whole post quite pointless
Now I will focus on understanding these MAP files.