diff --git a/cube.c b/cube.c
index 99f392a..69a9d35 100644
--- a/cube.c
+++ b/cube.c
@@ -171,7 +171,7 @@ enum { LEFT, RIGHT, UP, DOWN, UP_LEFT, UP_RIGHT, DOWN_LEFT, DOWN_RIGHT };
     (ra)[0] = rx; (ra)[1] = ry; (ra)[2] = rz; \
 } while (0)
 
-#define APPROXEQ(x,y) ( SQ(x-y) < 0.1 )
+#define APPROXEQ(x,y) ( SQ(x-y) < 0.1F )
 
 struct grid_square {
     float x, y;
@@ -787,7 +787,7 @@ static bool align_poly(const struct solid *solid, struct grid_square *sq,
             dist += SQ(solid->vertices[i*3+1] * flip - sq->points[j*2+1] + sq->y);
             dist += SQ(solid->vertices[i*3+2] - zmin);
 
-            if (dist < 0.1) {
+            if (dist < 0.1F) {
                 matches++;
                 index = i;
             }
@@ -837,7 +837,7 @@ static struct solid *transform_poly(const struct solid *solid, bool flip,
      */
     vx = ret->vertices[key1*3+0] - ret->vertices[key0*3+0];
     vy = ret->vertices[key1*3+1] - ret->vertices[key0*3+1];
-    assert(APPROXEQ(vx*vx + vy*vy, 1.0));
+    assert(APPROXEQ(vx*vx + vy*vy, 1.0F));
 
     vmatrix[0] =  vx; vmatrix[3] = vy; vmatrix[6] = 0;
     vmatrix[1] = -vy; vmatrix[4] = vx; vmatrix[7] = 0;
@@ -1091,11 +1091,11 @@ static int find_move_dest(const game_state *from, int direction,
             for (j = 0; j < from->grid->squares[i].npoints; j++) {
                 dist = (SQ(from->grid->squares[i].points[j*2] - points[0]) +
                         SQ(from->grid->squares[i].points[j*2+1] - points[1]));
-                if (dist < 0.1)
+                if (dist < 0.1F)
                     dkey[match++] = j;
                 dist = (SQ(from->grid->squares[i].points[j*2] - points[2]) +
                         SQ(from->grid->squares[i].points[j*2+1] - points[3]));
-                if (dist < 0.1)
+                if (dist < 0.1F)
                     dkey[match++] = j;
             }
 
diff --git a/drawing.c b/drawing.c
index 3584936..5fb8a31 100644
--- a/drawing.c
+++ b/drawing.c
@@ -90,8 +90,8 @@ void draw_line(drawing *dr, int x1, int y1, int x2, int y2, int colour)
 void draw_thick_line(drawing *dr, float thickness,
 		     float x1, float y1, float x2, float y2, int colour)
 {
-    if (thickness < 1.0)
-        thickness = 1.0;
+    if (thickness < 1.0F)
+        thickness = 1.0F;
     if (dr->api->draw_thick_line) {
 	dr->api->draw_thick_line(dr->handle, thickness,
 				 x1, y1, x2, y2, colour);
@@ -101,8 +101,8 @@ void draw_thick_line(drawing *dr, float thickness,
 	 * polygon rendering uses integer coordinates.
 	 */
 	float len = sqrt((x2 - x1)*(x2 - x1) + (y2 - y1)*(y2 - y1));
-	float tvhatx = (x2 - x1)/len * (thickness/2 - 0.2);
-	float tvhaty = (y2 - y1)/len * (thickness/2 - 0.2);
+	float tvhatx = (x2 - x1)/len * (thickness/2 - 0.2F);
+	float tvhaty = (y2 - y1)/len * (thickness/2 - 0.2F);
 	int p[8];
 
 	p[0] = x1 - tvhaty;
diff --git a/emcc.c b/emcc.c
index d634b7c..8037be4 100644
--- a/emcc.c
+++ b/emcc.c
@@ -1045,9 +1045,9 @@ int main(int argc, char **argv)
     for (i = 0; i < ncolours; i++) {
         char col[40];
         sprintf(col, "#%02x%02x%02x",
-                (unsigned)(0.5 + 255 * colours[i*3+0]),
-                (unsigned)(0.5 + 255 * colours[i*3+1]),
-                (unsigned)(0.5 + 255 * colours[i*3+2]));
+                (unsigned)(0.5F + 255 * colours[i*3+0]),
+                (unsigned)(0.5F + 255 * colours[i*3+1]),
+                (unsigned)(0.5F + 255 * colours[i*3+2]));
         colour_strings[i] = dupstr(col);
     }
     /* Put the background colour in a CSS variable. */
diff --git a/flip.c b/flip.c
index cc80b09..466a3af 100644
--- a/flip.c
+++ b/flip.c
@@ -1160,7 +1160,7 @@ static void draw_tile(drawing *dr, game_drawstate *ds, const game_state *state,
 	coords[7] = by + TILE_SIZE - (int)((float)TILE_SIZE * animtime);
 
 	colour = (tile & 1 ? COL_WRONG : COL_RIGHT);
-	if (animtime < 0.5)
+	if (animtime < 0.5F)
 	    colour = COL_WRONG + COL_RIGHT - colour;
 
 	draw_polygon(dr, coords, 4, colour, COL_GRID);
diff --git a/galaxies.c b/galaxies.c
index a789349..73356fb 100644
--- a/galaxies.c
+++ b/galaxies.c
@@ -2503,8 +2503,8 @@ static char *interpret_move(const game_state *state, game_ui *ui,
     int px, py;
     space *sp;
 
-    px = 2*FROMCOORD((float)x) + 0.5;
-    py = 2*FROMCOORD((float)y) + 0.5;
+    px = 2*FROMCOORD((float)x) + 0.5F;
+    py = 2*FROMCOORD((float)y) + 0.5F;
 
     if (button == 'C' || button == 'c') return dupstr("C");
 
@@ -2618,8 +2618,8 @@ static char *interpret_move(const game_state *state, game_ui *ui,
 
         ui->cur_visible = false;
 
-        px = (int)(2*FROMCOORD((float)x) + 0.5);
-        py = (int)(2*FROMCOORD((float)y) + 0.5);
+        px = (int)(2*FROMCOORD((float)x) + 0.5F);
+        py = (int)(2*FROMCOORD((float)y) + 0.5F);
 
         dot = NULL;
 
diff --git a/inertia.c b/inertia.c
index b47d58e..ed50c7a 100644
--- a/inertia.c
+++ b/inertia.c
@@ -1605,7 +1605,7 @@ static char *interpret_move(const game_state *state, game_ui *ui,
 	     * end up the right way round. */
 	    angle = atan2(dx, -dy);
 
-	    angle = (angle + (PI/8)) / (PI/4);
+	    angle = (angle + (float)(PI/8)) / (float)(PI/4);
 	    assert(angle > -16.0F);
 	    dir = (int)(angle + 16.0F) & 7;
 	}
diff --git a/net.c b/net.c
index 9ac2270..76273c2 100644
--- a/net.c
+++ b/net.c
@@ -2606,8 +2606,8 @@ static void draw_wires(drawing *dr, int cx, int cy, int radius,
 
     for (i = 0; i < npoints; i++) {
         rotated_coords(&xf, &yf, matrix, cx, cy, fpoints[2*i], fpoints[2*i+1]);
-        points[2*i] = 0.5 + xf;
-        points[2*i+1] = 0.5 + yf;
+        points[2*i] = 0.5F + xf;
+        points[2*i+1] = 0.5F + yf;
     }
 
     draw_polygon(dr, points, npoints, colour, colour);
@@ -2747,8 +2747,8 @@ static void draw_tile(drawing *dr, game_drawstate *ds, int x, int y,
      * rotated by an arbitrary angle about that centre point.
      */
     if (tile & TILE_ROTATING) {
-        matrix[0] = (float)cos(angle * PI / 180.0);
-        matrix[2] = (float)sin(angle * PI / 180.0);
+        matrix[0] = (float)cos(angle * (float)PI / 180.0F);
+        matrix[2] = (float)sin(angle * (float)PI / 180.0F);
     } else {
         matrix[0] = 1.0F;
         matrix[2] = 0.0F;
@@ -2787,8 +2787,8 @@ static void draw_tile(drawing *dr, game_drawstate *ds, int x, int y,
                 float x, y;
                 rotated_coords(&x, &y, matrix, cx, cy,
                                boxr * points[i], boxr * points[i+1]);
-                points[i] = x + 0.5;
-                points[i+1] = y + 0.5;
+                points[i] = x + 0.5F;
+                points[i+1] = y + 0.5F;
             }
 
             draw_polygon(dr, points, 4, col, COL_WIRE);
diff --git a/netslide.c b/netslide.c
index be83b7c..9305906 100644
--- a/netslide.c
+++ b/netslide.c
@@ -1492,7 +1492,7 @@ static void draw_tile(drawing *dr, game_drawstate *ds, const game_state *state,
         vx = (dy ? 1 : 0);
         vy = (dx ? 1 : 0);
 
-        if (xshift == 0.0 && yshift == 0.0 && (tile & dir)) {
+        if (xshift == 0.0F && yshift == 0.0F && (tile & dir)) {
             /*
              * If we are fully connected to the other tile, we must
              * draw right across the tile border. (We can use our
@@ -1696,7 +1696,7 @@ static void game_redraw(drawing *dr, game_drawstate *ds,
     /*
      * Draw any tile which differs from the way it was last drawn.
      */
-    if (xshift != 0.0 || yshift != 0.0) {
+    if (xshift != 0.0F || yshift != 0.0F) {
         active = compute_active(state,
                                 state->last_move_row, state->last_move_col);
     } else {
diff --git a/samegame.c b/samegame.c
index 121ed7d..57ce4b8 100644
--- a/samegame.c
+++ b/samegame.c
@@ -1554,7 +1554,7 @@ static void game_redraw(drawing *dr, game_drawstate *ds,
 	ds->started = true;
     }
 
-    if (flashtime > 0.0) {
+    if (flashtime > 0.0F) {
 	int frame = (int)(flashtime / FLASH_FRAME);
 	bgcolour = (frame % 2 ? COL_LOWLIGHT : COL_HIGHLIGHT);
     } else
diff --git a/twiddle.c b/twiddle.c
index 8c565a0..a8ed114 100644
--- a/twiddle.c
+++ b/twiddle.c
@@ -884,8 +884,8 @@ static void rotate(int *xy, struct rotation *rot)
 	xf2 = rot->c * xf + rot->s * yf;
 	yf2 = - rot->s * xf + rot->c * yf;
 
-	xy[0] = (int)(xf2 + rot->ox + 0.5);   /* round to nearest */
-	xy[1] = (int)(yf2 + rot->oy + 0.5);   /* round to nearest */
+	xy[0] = (int)(xf2 + rot->ox + 0.5F);   /* round to nearest */
+	xy[1] = (int)(yf2 + rot->oy + 0.5F);   /* round to nearest */
     }
 }
 
@@ -1072,7 +1072,7 @@ static int highlight_colour(float angle)
 	COL_LOWLIGHT,
     };
 
-    return colours[(int)((angle + 2*PI) / (PI/16)) & 31];
+    return colours[(int)((angle + 2*(float)PI) / ((float)PI/16)) & 31];
 }
 
 static float game_anim_length_real(const game_state *oldstate,
@@ -1196,7 +1196,7 @@ static void game_redraw(drawing *dr, game_drawstate *ds,
 	rot->cw = rot->ch = TILE_SIZE * state->n;
 	rot->ox = rot->cx + rot->cw/2;
 	rot->oy = rot->cy + rot->ch/2;
-	angle = (float)((-PI/2 * lastr) * (1.0 - animtime / anim_max));
+	angle = ((-(float)PI/2 * lastr) * (1.0F - animtime / anim_max));
 	rot->c = (float)cos(angle);
 	rot->s = (float)sin(angle);
 
diff --git a/undead.c b/undead.c
index 78abf28..1c52c27 100644
--- a/undead.c
+++ b/undead.c
@@ -1031,7 +1031,7 @@ static char *new_game_desc(const game_params *params, random_state *rs,
         /* Monsters / Mirrors ratio should be balanced */
         ratio = (float)new->common->num_total /
             (float)(new->common->params.w * new->common->params.h);
-        if (ratio < 0.48 || ratio > 0.78) {
+        if (ratio < 0.48F || ratio > 0.78F) {
             free_game(new);
             continue;
         }