A game made with Pygame is not playable in the browser. Games made with that tool can be put on itch, but only as a downloadable desktop package, not as a web game.
For completeness, I should mention there are a few projects that aim to get Python/Pygame working in a browser, but I would not call any of these a great option. The most prominent of these ...
This is known as a line-drawing algorithm. That link has multiple algorithms to solve this problem - for your case you'll want to ignore the algorithms which anti-alias. The simplest solution is the naive algorithm:
dx = x2 − x1
dy = y2 − y1
for x from x1 to x2 do
y = y1 + dy × (x − x1) / dx
(pseudocode copied from wikipedia)
A more ...
Even though the map is "small" at 100x100 with two layers, that's still 20,000 draw calls per frame.
One optimization is to only draw the tiles that are visible such as limiting your camera's viewable area and zoom levels so you can't see more than a few hundred tiles at once. You'll have to implement the ability to query if a tile is visible to ...