diff --git a/include/eepp/ui/css/propertyspecification.hpp b/include/eepp/ui/css/propertyspecification.hpp
index 7e4e09097..8169b6b2c 100644
--- a/include/eepp/ui/css/propertyspecification.hpp
+++ b/include/eepp/ui/css/propertyspecification.hpp
@@ -33,8 +33,15 @@ class EE_API PropertySpecification {
 
   protected:
 	friend class PropertyDefinition;
+
+// Investigate why robin_hood::unordered_flat_map fails with wasm build!
+#if EE_PLATFORM == EE_PLATFORM_EMSCRIPTEN
+	std::unordered_map<Uint32, std::shared_ptr<PropertyDefinition>> mProperties;
+	std::unordered_map<Uint32, std::shared_ptr<ShorthandDefinition>> mShorthands;
+#else
 	UnorderedMap<Uint32, std::shared_ptr<PropertyDefinition>> mProperties;
 	UnorderedMap<Uint32, std::shared_ptr<ShorthandDefinition>> mShorthands;
+#endif
 
 	const PropertyDefinition* addPropertyAlias( Uint32 aliasId, const PropertyDefinition* propDef );
 };
diff --git a/src/eepp/core/string.cpp b/src/eepp/core/string.cpp
index 537273e61..c43393c56 100644
--- a/src/eepp/core/string.cpp
+++ b/src/eepp/core/string.cpp
@@ -14,7 +14,8 @@
 #include <limits>
 #include <random>
 
-#if __GNUC__ >= 11 || ( __clang__ && __clang_major__ >= 12 )
+#if ( __GNUC__ >= 11 || ( __clang__ && __clang_major__ >= 12 ) ) && \
+	EE_PLATFORM != EE_PLATFORM_EMSCRIPTEN
 #define STD_SUPPORTS_FIXED_TO_CHARS
 #endif
 
diff --git a/src/eepp/graphics/textureatlasloader.cpp b/src/eepp/graphics/textureatlasloader.cpp
index 4fecbbdf3..4db841552 100644
--- a/src/eepp/graphics/textureatlasloader.cpp
+++ b/src/eepp/graphics/textureatlasloader.cpp
@@ -366,8 +366,7 @@ bool TextureAtlasLoader::updateTextureAtlas() {
 			fs.write( reinterpret_cast<char*>( tTexHdr ), sizeof( sTextureHdr ) );
 
 			fs.write( reinterpret_cast<char*>( &tTexAtlas->TextureRegions[0] ),
-					  sizeof( sTextureRegionHdr ) *
-						  (std::streamsize)tTexAtlas->TextureRegions.size() );
+					  sizeof( sTextureRegionHdr ) * (std::size_t)tTexAtlas->TextureRegions.size() );
 		}
 
 		return true;
diff --git a/src/eepp/graphics/texturepacker.cpp b/src/eepp/graphics/texturepacker.cpp
index 6817b5b7b..546d6a49e 100644
--- a/src/eepp/graphics/texturepacker.cpp
+++ b/src/eepp/graphics/texturepacker.cpp
@@ -727,7 +727,7 @@ void TexturePacker::saveTextureRegions() {
 
 		if ( tTextureRegionsHdr.size() )
 			fs.write( reinterpret_cast<const char*>( &tTextureRegionsHdr[0] ),
-					  sizeof( sTextureRegionHdr ) * (std::streamsize)tTextureRegionsHdr.size() );
+					  sizeof( sTextureRegionHdr ) * tTextureRegionsHdr.size() );
 	}
 }
 
diff --git a/src/tools/ecode/version.cpp b/src/tools/ecode/version.cpp
index 65b8222f5..d2d8ecaf6 100644
--- a/src/tools/ecode/version.cpp
+++ b/src/tools/ecode/version.cpp
@@ -1,4 +1,5 @@
 #include "version.hpp"
+#include <cinttypes>
 #include <eepp/core/string.hpp>
 
 namespace ecode {
@@ -13,12 +14,12 @@ Uint64 Version::getVersionNum() {
 	Version ver = getVersion();
 	return ECODE_VERSIONNUM( ver.major, ver.minor, ver.patch, ver.commit );
 }
-
 std::string Version::getVersionNumString() {
 	Version ver = getVersion();
 	if ( ver.commit > 0 && ver.commit < 9999 )
-		return String::format( "%d.%d.%d-%d", ver.major, ver.minor, ver.patch, ver.commit );
-	return String::format( "%d.%d.%d", ver.major, ver.minor, ver.patch );
+		return String::format( "%" PRIu64 ".%" PRIu64 ".%" PRIu64 "-%" PRIu64, ver.major, ver.minor,
+							   ver.patch, ver.commit );
+	return String::format( "%" PRIu64 ".%" PRIu64 ".%" PRIu64, ver.major, ver.minor, ver.patch );
 }
 
 std::string Version::getVersionFullName() {