Let go of the D-pad

Getting in at all

Writing a map number into wCurMap crashes the game. The whole map header sits underneath it, so the engine ends up reading the new map's blocks through the old map's pointers.

The safe route is wWarpEntries: redirect one of the current room's own warps at the target map and walk the player into it. The engine loads the destination header itself — LoadMapHeader, the tileset copy into video RAM, the palette, the objects, the screen. Everything after the walk is the game's own.

So PixelGB plays the opening, saves the machine's state the moment it stands on a real map, and for each of the 226 maps rewinds to that moment, points one warp at the target and walks in.

And then one line was worth a hundred maps

A door is a warp on both sides. You arrive on the doormat, and a player still holding the direction takes one more step and walks straight back out.

Holding: 113 maps photographed. Releasing on arrival: 216.

The one that was stranger: shop clerks talk

Several maps put a text box up the moment you arrive, and Generation 1 does that by parking the window layer at WY = 0. Which means the window covers the entire screen and the map is drawn through it.

An earlier version of the comparison excluded "wherever the window is", the way it excludes sprites — and so masked the whole picture. 31 maps went from exact to inconclusive and two to no-alignment, with nothing in the report to say why.

The right answer was not to subtract the text box but to dismiss it, the way a player does: press B until the window is off-screen again, requiring several consecutive clear checks, because the window parks off-screen for a few frames between two boxes of one conversation.

It looked like a tolerance problem and it was a modelling one.

What it did not rescue

The Hall of Fame. Walk in and Oak starts talking, and his script is not one you can press B through — it inducts the party. PixelGB presses B up to eighty times and requires four consecutive clear checks before photographing; this one still has a text box up when the budget runs out, so it is counted on its own.

Ten more maps have nowhere to arrive: a warp names a destination warp on the far side and these have none, so the camera comes to rest outside the map. Those and the Hall of Fame are the eleven named on the project page.