diff --git a/.github/workflows/mingw-w64.yml b/.github/workflows/mingw-w64.yml
index 3f8172e9a575..8e5db39a5fa1 100644
--- a/.github/workflows/mingw-w64.yml
+++ b/.github/workflows/mingw-w64.yml
@@ -80,7 +80,7 @@ jobs:
         shell: msys2 {0}
         run: |
           mkdir bin
-          cc crystal.obj -o bin/crystal.exe \
+          cc crystal.obj -o bin/crystal.exe -municode \
             $(pkg-config bdw-gc libpcre2-8 iconv zlib libffi --libs) \
             $(llvm-config --libs --system-libs --ldflags) \
             -lole32 -lWS2_32 -Wl,--stack,0x800000
diff --git a/spec/std/socket/socket_spec.cr b/spec/std/socket/socket_spec.cr
index 65f7ed72a453..8bb7349318c6 100644
--- a/spec/std/socket/socket_spec.cr
+++ b/spec/std/socket/socket_spec.cr
@@ -87,6 +87,8 @@ describe Socket, tags: "network" do
 
     expect_raises(IO::TimeoutError) { server.accept }
     expect_raises(IO::TimeoutError) { server.accept? }
+  ensure
+    server.try &.close
   end
 
   it "sends messages" do
diff --git a/spec/std/socket/udp_socket_spec.cr b/spec/std/socket/udp_socket_spec.cr
index 6b349072294d..a84a6adebc74 100644
--- a/spec/std/socket/udp_socket_spec.cr
+++ b/spec/std/socket/udp_socket_spec.cr
@@ -28,6 +28,8 @@ describe UDPSocket, tags: "network" do
       socket = UDPSocket.new(family)
       socket.bind(address, 0)
       socket.local_address.address.should eq address
+    ensure
+      socket.try &.close
     end
 
     it "sends and receives messages" do
diff --git a/src/compiler/crystal/loader/mingw.cr b/src/compiler/crystal/loader/mingw.cr
index 677f564cec16..2c557a893640 100644
--- a/src/compiler/crystal/loader/mingw.cr
+++ b/src/compiler/crystal/loader/mingw.cr
@@ -7,6 +7,8 @@ require "crystal/system/win32/library_archive"
 # The core implementation is derived from the MSVC loader. Main deviations are:
 #
 # - `.parse` follows GNU `ld`'s style, rather than MSVC `link`'s;
+# - `.parse` automatically inserts a C runtime library if `-mcrtdll` isn't
+#   supplied;
 # - `#library_filename` follows the usual naming of the MinGW linker: `.dll.a`
 #   for DLL import libraries, `.a` for other libraries;
 # - `.default_search_paths` relies solely on `.cc_each_library_path`.
@@ -28,6 +30,11 @@ class Crystal::Loader
     file_paths = [] of String
     extra_search_paths = [] of String
 
+    # note that `msvcrt` is a default runtime chosen at MinGW-w64 build time,
+    # `ucrt` is always UCRT (even in a MINGW64 environment), and
+    # `msvcrt-os` is always MSVCRT (even in a UCRT64 environment)
+    crt_dll = "msvcrt"
+
     OptionParser.parse(args.dup) do |parser|
       parser.on("-L DIRECTORY", "--library-path DIRECTORY", "Add DIRECTORY to library search path") do |directory|
         extra_search_paths << directory
@@ -39,17 +46,21 @@ class Crystal::Loader
         raise LoadError.new "static libraries are not supported by Crystal's runtime loader"
       end
       parser.unknown_args do |args, after_dash|
-        file_paths.concat args
+        file_paths.concat args.reject(&.starts_with?("-mcrtdll="))
       end
 
       parser.invalid_option do |arg|
-        unless arg.starts_with?("-Wl,")
+        if crt_dll_arg = arg.lchop?("-mcrtdll=")
+          # the GCC spec is `%{!mcrtdll=*:-lmsvcrt} %{mcrtdll=*:-l%*}`
+          crt_dll = crt_dll_arg
+        elsif !arg.starts_with?("-Wl,")
           raise LoadError.new "Not a recognized linker flag: #{arg}"
         end
       end
     end
 
     search_paths = extra_search_paths + search_paths
+    libnames << crt_dll
 
     begin
       loader = new(search_paths)
diff --git a/src/crystal/system/win32/wmain.cr b/src/crystal/system/win32/wmain.cr
index caad6748229f..2120bfc06bfc 100644
--- a/src/crystal/system/win32/wmain.cr
+++ b/src/crystal/system/win32/wmain.cr
@@ -2,14 +2,12 @@ require "c/stringapiset"
 require "c/winnls"
 require "c/stdlib"
 
-{% begin %}
-  # we have both `main` and `wmain`, so we must choose an unambiguous entry point
+# we have both `main` and `wmain`, so we must choose an unambiguous entry point
+{% if flag?(:msvc) %}
   @[Link({{ flag?(:static) ? "libcmt" : "msvcrt" }})]
-  {% if flag?(:msvc) %}
-    @[Link(ldflags: "/ENTRY:wmainCRTStartup")]
-  {% elsif flag?(:gnu) && !flag?(:interpreted) %}
-    @[Link(ldflags: "-municode")]
-  {% end %}
+  @[Link(ldflags: "/ENTRY:wmainCRTStartup")]
+{% elsif flag?(:gnu) && !flag?(:interpreted) %}
+  @[Link(ldflags: "-municode")]
 {% end %}
 lib LibCrystalMain
 end
diff --git a/src/dir/glob.cr b/src/dir/glob.cr
index cd45f0a03baf..2fc8d988c20a 100644
--- a/src/dir/glob.cr
+++ b/src/dir/glob.cr
@@ -37,6 +37,10 @@ class Dir
 
   # Returns an array of all files that match against any of *patterns*.
   #
+  # ```
+  # Dir.glob "path/to/folder/*.txt" # Returns all files in the target folder that end in ".txt".
+  # Dir.glob "path/to/folder/**/*"  # Returns all files in the target folder and its subfolders.
+  # ```
   # The pattern syntax is similar to shell filename globbing, see `File.match?` for details.
   #
   # NOTE: Path separator in patterns needs to be always `/`. The returned file names use system-specific path separators.
diff --git a/src/empty.cr b/src/empty.cr
index 204e30da48c0..cb79610a5be3 100644
--- a/src/empty.cr
+++ b/src/empty.cr
@@ -1,6 +1,6 @@
 require "primitives"
 
-{% if flag?(:win32) %}
+{% if flag?(:msvc) %}
   @[Link({{ flag?(:static) ? "libcmt" : "msvcrt" }})] # For `mainCRTStartup`
 {% end %}
 lib LibCrystalMain
diff --git a/src/gc/none.cr b/src/gc/none.cr
index ce84027e6e69..651027266e5b 100644
--- a/src/gc/none.cr
+++ b/src/gc/none.cr
@@ -1,5 +1,6 @@
 {% if flag?(:win32) %}
   require "c/process"
+  require "c/heapapi"
 {% end %}
 require "crystal/tracing"
 
@@ -11,21 +12,42 @@ module GC
   # :nodoc:
   def self.malloc(size : LibC::SizeT) : Void*
     Crystal.trace :gc, "malloc", size: size
-    # libc malloc is not guaranteed to return cleared memory, so we need to
-    # explicitly clear it. Ref: https://github.com/crystal-lang/crystal/issues/14678
-    LibC.malloc(size).tap(&.clear)
+
+    {% if flag?(:win32) %}
+      LibC.HeapAlloc(LibC.GetProcessHeap, LibC::HEAP_ZERO_MEMORY, size)
+    {% else %}
+      # libc malloc is not guaranteed to return cleared memory, so we need to
+      # explicitly clear it. Ref: https://github.com/crystal-lang/crystal/issues/14678
+      LibC.malloc(size).tap(&.clear)
+    {% end %}
   end
 
   # :nodoc:
   def self.malloc_atomic(size : LibC::SizeT) : Void*
     Crystal.trace :gc, "malloc", size: size, atomic: 1
-    LibC.malloc(size)
+
+    {% if flag?(:win32) %}
+      LibC.HeapAlloc(LibC.GetProcessHeap, 0, size)
+    {% else %}
+      LibC.malloc(size)
+    {% end %}
   end
 
   # :nodoc:
   def self.realloc(pointer : Void*, size : LibC::SizeT) : Void*
     Crystal.trace :gc, "realloc", size: size
-    LibC.realloc(pointer, size)
+
+    {% if flag?(:win32) %}
+      # realloc with a null pointer should behave like plain malloc, but Win32
+      # doesn't do that
+      if pointer
+        LibC.HeapReAlloc(LibC.GetProcessHeap, LibC::HEAP_ZERO_MEMORY, pointer, size)
+      else
+        LibC.HeapAlloc(LibC.GetProcessHeap, LibC::HEAP_ZERO_MEMORY, size)
+      end
+    {% else %}
+      LibC.realloc(pointer, size)
+    {% end %}
   end
 
   def self.collect
@@ -39,7 +61,12 @@ module GC
 
   def self.free(pointer : Void*) : Nil
     Crystal.trace :gc, "free"
-    LibC.free(pointer)
+
+    {% if flag?(:win32) %}
+      LibC.HeapFree(LibC.GetProcessHeap, 0, pointer)
+    {% else %}
+      LibC.free(pointer)
+    {% end %}
   end
 
   def self.is_heap_ptr(pointer : Void*) : Bool
diff --git a/src/levenshtein.cr b/src/levenshtein.cr
index e890d59c90ef..01ad1bc40784 100644
--- a/src/levenshtein.cr
+++ b/src/levenshtein.cr
@@ -139,7 +139,7 @@ module Levenshtein
   # end
   # best_match # => "ello"
   # ```
-  def self.find(name, tolerance = nil, &)
+  def self.find(name, tolerance = nil, &) : String?
     Finder.find(name, tolerance) do |sn|
       yield sn
     end
@@ -154,7 +154,7 @@ module Levenshtein
   # Levenshtein.find("hello", ["hullo", "hel", "hall", "hell"], 2) # => "hullo"
   # Levenshtein.find("hello", ["hurlo", "hel", "hall"], 1)         # => nil
   # ```
-  def self.find(name, all_names, tolerance = nil)
+  def self.find(name, all_names, tolerance = nil) : String?
     Finder.find(name, all_names, tolerance)
   end
 end
diff --git a/src/lib_c.cr b/src/lib_c.cr
index 0bd8d2c2cc35..7bc94a34f53e 100644
--- a/src/lib_c.cr
+++ b/src/lib_c.cr
@@ -1,4 +1,4 @@
-{% if flag?(:win32) %}
+{% if flag?(:msvc) %}
   @[Link({{ flag?(:static) ? "libucrt" : "ucrt" }})]
 {% end %}
 lib LibC
diff --git a/src/lib_c/x86_64-windows-msvc/c/heapapi.cr b/src/lib_c/x86_64-windows-msvc/c/heapapi.cr
index 1738cf774cac..8db5152585bc 100644
--- a/src/lib_c/x86_64-windows-msvc/c/heapapi.cr
+++ b/src/lib_c/x86_64-windows-msvc/c/heapapi.cr
@@ -1,6 +1,8 @@
 require "c/winnt"
 
 lib LibC
+  HEAP_ZERO_MEMORY = 0x00000008
+
   fun GetProcessHeap : HANDLE
   fun HeapAlloc(hHeap : HANDLE, dwFlags : DWORD, dwBytes : SizeT) : Void*
   fun HeapReAlloc(hHeap : HANDLE, dwFlags : DWORD, lpMem : Void*, dwBytes : SizeT) : Void*
diff --git a/src/string.cr b/src/string.cr
index 09272c80eb45..273472d34517 100644
--- a/src/string.cr
+++ b/src/string.cr
@@ -1798,11 +1798,7 @@ class String
   def rchop? : String?
     return if empty?
 
-    if to_unsafe[bytesize - 1] < 0x80 || single_byte_optimizable?
-      return unsafe_byte_slice_string(0, bytesize - 1)
-    end
-
-    self[0, size - 1]
+    unsafe_byte_slice_string(0, Char::Reader.new(at_end: self).pos, @length > 0 ? @length - 1 : 0)
   end
 
   # Returns a new `String` with *suffix* removed from the end of the string if possible, else returns `nil`.