diff --git a/source/build/include/build.h b/source/build/include/build.h
index 9645964a6..80c086141 100644
--- a/source/build/include/build.h
+++ b/source/build/include/build.h
@@ -390,7 +390,7 @@ void   neartag(int32_t xs, int32_t ys, int32_t zs, int16_t sectnum, int16_t ange
                int32_t (*blacklist_sprite_func)(int32_t) = nullptr) ATTRIBUTE((nonnull(6,7,8)));
 int32_t   cansee(int32_t x1, int32_t y1, int32_t z1, int16_t sect1,
                  int32_t x2, int32_t y2, int32_t z2, int16_t sect2);
-int32_t   inside(int32_t x, int32_t y, int16_t sectnum);
+int32_t   inside(int32_t x, int32_t y, int sectnum);
 void   dragpoint(int16_t pointhighlight, int32_t dax, int32_t day, uint8_t flags = 0);
 int32_t try_facespr_intersect(uspriteptr_t const spr, vec3_t const in,
                                      int32_t vx, int32_t vy, int32_t vz,
@@ -418,9 +418,9 @@ inline int32_t krand(void)
 int32_t    krand(void);
 #endif
 
-inline int32_t ksqrt(uint32_t num)
+inline int32_t ksqrt(uint64_t num)
 {
-    return int(sqrt((float)num));
+    return int(sqrt(double(num)));
 }
 
 int32_t   getangle(int32_t xvect, int32_t yvect);
@@ -459,36 +459,36 @@ void yax_getzsofslope(int sectNum, int playerX, int playerY, int32_t* pCeilZ, in
 int32_t yax_getceilzofslope(int const sectnum, vec2_t const vect);
 int32_t yax_getflorzofslope(int const sectnum, vec2_t const vect);
 
-inline int32_t getceilzofslope(int16_t sectnum, int32_t dax, int32_t day)
+inline int32_t getceilzofslope(int sectnum, int32_t dax, int32_t day)
 {
     return getceilzofslopeptr((usectorptr_t)&sector[sectnum], dax, day);
 }
 
-inline int32_t getflorzofslope(int16_t sectnum, int32_t dax, int32_t day)
+inline int32_t getflorzofslope(int sectnum, int32_t dax, int32_t day)
 {
     return getflorzofslopeptr((usectorptr_t)&sector[sectnum], dax, day);
 }
 
-inline void getzsofslope(int16_t sectnum, int32_t dax, int32_t day, int32_t *ceilz, int32_t *florz)
+inline void getzsofslope(int sectnum, int32_t dax, int32_t day, int32_t *ceilz, int32_t *florz)
 {
     getzsofslopeptr((usectorptr_t)&sector[sectnum], dax, day, ceilz, florz);
 }
 
-inline void getcorrectzsofslope(int16_t sectnum, int32_t dax, int32_t day, int32_t *ceilz, int32_t *florz)
+inline void getcorrectzsofslope(int sectnum, int32_t dax, int32_t day, int32_t *ceilz, int32_t *florz)
 {
     vec2_t closest = { dax, day };
     getsectordist(closest, sectnum, &closest);
     getzsofslopeptr((usectorptr_t)&sector[sectnum], closest.x, closest.y, ceilz, florz);
 }
 
-inline int32_t getcorrectceilzofslope(int16_t sectnum, int32_t dax, int32_t day)
+inline int32_t getcorrectceilzofslope(int sectnum, int32_t dax, int32_t day)
 {
     vec2_t closest = { dax, day };
     getsectordist(closest, sectnum, &closest);
     return getceilzofslopeptr((usectorptr_t)&sector[sectnum], closest.x, closest.y);
 }
 
-inline int32_t getcorrectflorzofslope(int16_t sectnum, int32_t dax, int32_t day)
+inline int32_t getcorrectflorzofslope(int sectnum, int32_t dax, int32_t day)
 {
     vec2_t closest = { dax, day };
     getsectordist(closest, sectnum, &closest);
diff --git a/source/build/src/clip.cpp b/source/build/src/clip.cpp
index 109d34380..2a3ba6352 100644
--- a/source/build/src/clip.cpp
+++ b/source/build/src/clip.cpp
@@ -295,7 +295,7 @@ static inline int32_t cliptrace(vec2_t const pos, vec2_t * const goal)
 {
     int32_t hitwall = -1;
 
-    for (native_t z=clipnum-1; z>=0; z--)
+    for (int z=clipnum-1; z>=0; z--)
     {
         vec2_t const p1   = { clipit[z].x1, clipit[z].y1 };
         vec2_t const p2   = { clipit[z].x2, clipit[z].y2 };
@@ -716,13 +716,13 @@ int32_t clipmove(vec3_t * const pos, int16_t * const sectnum, int32_t xvect, int
     int32_t hitwalls[4], hitwall;
     int32_t clipReturn = 0;
 
-    native_t cnt = clipmoveboxtracenum;
+    int cnt = clipmoveboxtracenum;
 
     do
     {
         if (enginecompatibility_mode == ENGINECOMPATIBILITY_NONE && (xvect|yvect)) 
         {
-            for (native_t i=clipnum-1;i>=0;--i)
+            for (int i=clipnum-1;i>=0;--i)
             {
                 if (!bitmap_test(clipignore, i) && clipinsideboxline(pos->x, pos->y, clipit[i].x1, clipit[i].y1, clipit[i].x2, clipit[i].y2, walldist))
                 {
@@ -750,7 +750,7 @@ int32_t clipmove(vec3_t * const pos, int16_t * const sectnum, int32_t xvect, int
                 int32_t const templl2
                 = (int32_t)clamp(compat_maybe_truncate_to_int32((int64_t)(goal.x - vec.x) * clipr.x + (int64_t)(goal.y - vec.y) * clipr.y), INT32_MIN, INT32_MAX);
                 int32_t const i = (enginecompatibility_mode == ENGINECOMPATIBILITY_19950829 || (abs(templl2)>>11) < templl) ?
-                    DivScaleL(templl2, templl, 20) : 0;
+                    (int)DivScaleL(templl2, templl, 20) : 0;
 
                 goal = { MulScale(clipr.x, i, 20)+vec.x, MulScale(clipr.y, i, 20)+vec.y };
             }
@@ -807,7 +807,7 @@ int32_t clipmove(vec3_t * const pos, int16_t * const sectnum, int32_t xvect, int
 
         int32_t tempint2, tempint1 = INT32_MAX;
         *sectnum = -1;
-        for (native_t j=numsectors-1; j>=0; j--)
+        for (int j=numsectors-1; j>=0; j--)
             if (inside(pos->x, pos->y, j) == 1)
             {
                 if (enginecompatibility_mode != ENGINECOMPATIBILITY_19950829 && (sector[j].ceilingstat&2))
@@ -819,7 +819,8 @@ int32_t clipmove(vec3_t * const pos, int16_t * const sectnum, int32_t xvect, int
                 {
                     if (tempint2 < tempint1)
                     {
-                        *sectnum = j; tempint1 = tempint2;
+                        *sectnum = (int16_t)j; 
+                        tempint1 = tempint2;
                     }
                 }
                 else
@@ -831,12 +832,13 @@ int32_t clipmove(vec3_t * const pos, int16_t * const sectnum, int32_t xvect, int
 
                     if (tempint2 <= 0)
                     {
-                        *sectnum = j;
+                        *sectnum = (int16_t)j;
                         return clipReturn;
                     }
                     if (tempint2 < tempint1)
                     {
-                        *sectnum = j; tempint1 = tempint2;
+                        *sectnum = (int16_t)j;
+                        tempint1 = tempint2;
                     }
                 }
             }
@@ -1257,9 +1259,9 @@ static int32_t hitscan_trysector(const vec3_t *sv, usectorptr_t sec, hitdata_t *
     {
         if (tmp==NULL)
         {
-            if (inside(x1,y1,sec-sector) == 1)
+            if (inside(x1,y1,int(sec-sector)) == 1)
             {
-                hit_set(hit, sec-sector, -1, -1, x1, y1, z1);
+                hit_set(hit, int(sec-sector), -1, -1, x1, y1, z1);
                 hitscan_hitsectcf = (how+1)>>1;
             }
         }
@@ -1267,12 +1269,12 @@ static int32_t hitscan_trysector(const vec3_t *sv, usectorptr_t sec, hitdata_t *
         {
             const int32_t curidx=(int32_t)tmp[0];
             auto const curspr=(spritetype *)tmp[1];
-            const int32_t thislastsec = tmp[2];
+            const int32_t thislastsec = (int32_t)tmp[2];
 
             if (!thislastsec)
             {
-                if (inside(x1,y1,sec-sector) == 1)
-                    hit_set(hit, curspr->sectnum, -1, curspr-sprite, x1, y1, z1);
+                if (inside(x1,y1,int(sec-sector)) == 1)
+                    hit_set(hit, int(curspr->sectnum), -1, int(curspr-sprite), x1, y1, z1);
             }
         }
     }
diff --git a/source/build/src/engine.cpp b/source/build/src/engine.cpp
index a7e2a68c8..8e0f7896d 100644
--- a/source/build/src/engine.cpp
+++ b/source/build/src/engine.cpp
@@ -778,7 +778,7 @@ int32_t inside_old(int32_t x, int32_t y, int16_t sectnum)
     return -1;
 }
 
-int32_t inside(int32_t x, int32_t y, int16_t sectnum)
+int32_t inside(int32_t x, int32_t y, int sectnum)
 {
     switch (enginecompatibility_mode)
     {
diff --git a/source/build/src/mdsprite.cpp b/source/build/src/mdsprite.cpp
index bac6b65cf..157dc1f23 100644
--- a/source/build/src/mdsprite.cpp
+++ b/source/build/src/mdsprite.cpp
@@ -19,6 +19,12 @@
 #include "hw_voxels.h"
 #include "../../glbackend/glbackend.h"
 
+#ifdef _MSC_VER
+// just make it shut up. Most of this file will go down the drain anyway soon.
+#pragma warning(disable:4244) 
+#pragma warning(disable:4267) 
+#endif
+
 static int32_t curextra=MAXTILES;
 
 #define MIN_CACHETIME_PRINT 10
diff --git a/source/build/src/polymost.cpp b/source/build/src/polymost.cpp
index a8a7572bc..95d4bef9d 100644
--- a/source/build/src/polymost.cpp
+++ b/source/build/src/polymost.cpp
@@ -28,6 +28,10 @@ Ken Silverman's official web site: http://www.advsys.net/ken
 #include "gamestruct.h"
 #include "hw_voxels.h"
 
+#ifdef _MSC_VER
+// just make it shut up. Most of this file will go down the drain anyway soon.
+#pragma warning(disable:4244) 
+#endif
 
 typedef struct {
     union { double x; double d; };
@@ -309,7 +313,7 @@ static void polymost_updaterotmat(void)
     renderSetVisibility(g_visibility * fxdimen * (1.f / (65536.f)) / r_ambientlight);
 }
 
-const vec2_16_t tileSize(size_t index)
+const vec2_16_t tileSize(int index)
 {
     vec2_16_t v = { (int16_t)tileWidth(index), (int16_t)tileHeight(index) };
     return v;