What's kinda weird is that you can see a lot more of the map than on the on calc version or any RPG for that matter.

Yeah normally you just can see around 20x15 tiles at once. I think he just setup his game to be 512x448, but the tiles are 16x16 instead of 32x32. If I would make an HP Prime version and I didn't want to redo all tiles from scratch, I would probably use 160x120. Else it reminds me a bit of RPG Maker 95.

For reference, this is how it looks like from the CSE demo thing (tilemapper mostly coded by tr1p1ea)