Fish Fillets - Next Generation (4e47409, 1.0.1) for fredygames.com (GPL-2.0-or-later, like the game): the
game was written for SDL 1.2, and this browser build runs it on SDL2 (Emscripten's port) with
compat/SDL.h and compat/sdl12shim.cpp (published next to this patch), which provide the few SDL 1.2
calls the game uses. What changes in the game itself:

- effect/*, level/ShapeBuilder.cpp: SDL_Color's fourth member is called "a" in SDL2 (it was "unused");
- effect/Outline.cpp, effect/PixelIterator.cpp: the colour key of a surface is read with
  fy_GetColorKey() (SDL2 has no format->colorkey);
- gengine/KeyStroke.cpp: the typed character (keysym.unicode in SDL 1.2) comes from fy_Unicode().

diff -ruN a/src/effect/Color.h b/src/effect/Color.h
--- a/src/effect/Color.h	2011-09-08 15:21:47.000000000 -0300
+++ b/src/effect/Color.h	2026-11-01 20:20:06.131271128 -0300
@@ -13,7 +13,7 @@
             this->r = red;
             this->g = green;
             this->b = blue;
-            this->unused = alpha;
+            this->a = alpha;
         }
 };
 
diff -ruN a/src/effect/EffectDisintegrate.cpp b/src/effect/EffectDisintegrate.cpp
--- a/src/effect/EffectDisintegrate.cpp	2011-09-08 15:21:47.000000000 -0300
+++ b/src/effect/EffectDisintegrate.cpp	2026-11-01 20:20:06.130824177 -0300
@@ -63,7 +63,7 @@
         for (int px = 0; px < surface->w; ++px) {
             if (Random::aByte(py * surface->w + px) < m_disint) {
                 SDL_Color pixel = PixelTool::getColor(surface, px, py);
-                if (pixel.unused == 255) {
+                if (pixel.a == 255) {
                     PixelTool::putColor(screen, x + px, y + py, pixel);
                 }
             }
diff -ruN a/src/effect/EffectMirror.cpp b/src/effect/EffectMirror.cpp
--- a/src/effect/EffectMirror.cpp	2011-09-08 15:21:47.000000000 -0300
+++ b/src/effect/EffectMirror.cpp	2026-11-01 20:20:06.131924826 -0300
@@ -36,7 +36,7 @@
                 PixelTool::putColor(screen, x + px, y + py, sample);
             }
             else {
-                if (pixel.unused == 255) {
+                if (pixel.a == 255) {
                     PixelTool::putColor(screen, x + px, y + py, pixel);
                 }
             }
diff -ruN a/src/effect/EffectReverse.cpp b/src/effect/EffectReverse.cpp
--- a/src/effect/EffectReverse.cpp	2011-09-08 15:21:47.000000000 -0300
+++ b/src/effect/EffectReverse.cpp	2026-11-01 20:20:06.132352361 -0300
@@ -25,7 +25,7 @@
     for (int py = 0; py < surface->h; ++py) {
         for (int px = 0; px < surface->w; ++px) {
             SDL_Color pixel = PixelTool::getColor(surface, px, py);
-            if (pixel.unused == 255) {
+            if (pixel.a == 255) {
                 PixelTool::putColor(screen,
                         x + surface->w - 1 - px, y + py, pixel);
             }
diff -ruN a/src/effect/LayeredPicture.cpp b/src/effect/LayeredPicture.cpp
--- a/src/effect/LayeredPicture.cpp	2011-09-08 15:21:47.000000000 -0300
+++ b/src/effect/LayeredPicture.cpp	2026-11-01 20:20:06.131603789 -0300
@@ -98,7 +98,7 @@
 
             if (sample == m_activeColor) {
                 SDL_Color lower = PixelTool::getColor(m_lowerLayer, px, py);
-                if (lower.unused == 255) {
+                if (lower.a == 255) {
                     PixelTool::putColor(screen,
                             m_loc.getX() + px, world_y, lower);
                 }
diff -ruN a/src/effect/Outline.cpp b/src/effect/Outline.cpp
--- a/src/effect/Outline.cpp	2011-09-08 15:21:47.000000000 -0300
+++ b/src/effect/Outline.cpp	2026-11-01 20:19:49.490709826 -0300
@@ -27,7 +27,7 @@
 void
 Outline::drawOnColorKey(SDL_Surface *surface)
 {
-    Uint32 bgKey = surface->format->colorkey;
+    Uint32 bgKey = fy_GetColorKey(surface);
     drawOn(surface, bgKey);
 }
 //-----------------------------------------------------------------
diff -ruN a/src/effect/PixelIterator.cpp b/src/effect/PixelIterator.cpp
--- a/src/effect/PixelIterator.cpp	2011-09-08 15:21:47.000000000 -0300
+++ b/src/effect/PixelIterator.cpp	2026-11-01 20:20:06.133538466 -0300
@@ -49,7 +49,7 @@
 bool
 PixelIterator::isTransparent() const
 {
-    return getPixel() == m_surface->format->colorkey;
+    return getPixel() == fy_GetColorKey(m_surface);
 }
 //-----------------------------------------------------------------
 SDL_Color
@@ -57,7 +57,7 @@
 {
     SDL_Color color;
     SDL_GetRGBA(getPixel(), m_surface->format,
-            &color.r, &color.g, &color.b, &color.unused);
+            &color.r, &color.g, &color.b, &color.a);
     return color;
 }
 //-----------------------------------------------------------------
@@ -71,7 +71,7 @@
 PixelIterator::putColor(const SDL_Color &color)
 {
     Uint32 pixel = SDL_MapRGBA(m_surface->format,
-            color.r, color.g, color.b, color.unused);
+            color.r, color.g, color.b, color.a);
     putPixel(pixel);
 }
 //-----------------------------------------------------------------
diff -ruN a/src/effect/PixelTool.cpp b/src/effect/PixelTool.cpp
--- a/src/effect/PixelTool.cpp	2011-09-08 15:21:47.000000000 -0300
+++ b/src/effect/PixelTool.cpp	2026-11-01 20:20:06.132789937 -0300
@@ -41,7 +41,7 @@
 {
     SDL_Color color;
     SDL_GetRGBA(getPixel(surface, x, y), surface->format,
-            &color.r, &color.g, &color.b, &color.unused);
+            &color.r, &color.g, &color.b, &color.a);
     return color;
 }
 //-----------------------------------------------------------------
@@ -55,7 +55,7 @@
         const SDL_Color &color)
 {
     Uint32 pixel = SDL_MapRGBA(surface->format,
-            color.r, color.g, color.b, color.unused);
+            color.r, color.g, color.b, color.a);
     putPixel(surface, x, y, pixel);
 }
 //-----------------------------------------------------------------
diff -ruN a/src/effect/SurfaceTool.cpp b/src/effect/SurfaceTool.cpp
--- a/src/effect/SurfaceTool.cpp	2011-09-08 15:21:47.000000000 -0300
+++ b/src/effect/SurfaceTool.cpp	2026-11-01 20:20:06.133192347 -0300
@@ -98,7 +98,7 @@
     SDL_Surface *canvas = createEmpty(surface, w, h);
     Uint32 pixel = SDL_MapRGB(canvas->format, color.r, color.g, color.b);
     SDL_FillRect(canvas, NULL, pixel);
-    SDL_SetAlpha(canvas, SDL_SRCALPHA|SDL_RLEACCEL, color.unused);
+    SDL_SetAlpha(canvas, SDL_SRCALPHA|SDL_RLEACCEL, color.a);
 
     SDL_BlitSurface(canvas, NULL, surface, dstrect);
     SDL_FreeSurface(canvas);
diff -ruN a/src/gengine/KeyStroke.cpp b/src/gengine/KeyStroke.cpp
--- a/src/gengine/KeyStroke.cpp	2011-09-08 15:21:47.000000000 -0300
+++ b/src/gengine/KeyStroke.cpp	2026-11-01 20:19:49.494672595 -0300
@@ -18,7 +18,7 @@
 {
     m_sym = keysym.sym;
     m_mod = modStrip(keysym.mod);
-    m_unicode = keysym.unicode;
+    m_unicode = fy_Unicode(keysym.sym, keysym.mod);
 }
 //-----------------------------------------------------------------
 /**
diff -ruN a/src/level/ShapeBuilder.cpp b/src/level/ShapeBuilder.cpp
--- a/src/level/ShapeBuilder.cpp	2011-09-08 15:21:47.000000000 -0300
+++ b/src/level/ShapeBuilder.cpp	2026-11-01 20:20:06.133912669 -0300
@@ -28,7 +28,7 @@
     color->r = 0;
     color->g = 0;
     color->b = 0;
-    color->unused = 255;
+    color->a = 255;
 
     switch (weight) {
         case Cube::LIGHT: