diff --git a/Gemfile.lock b/Gemfile.lock
index 54324a7..6331a43 100755
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -20,6 +20,7 @@ GEM
     mocha (1.0.0)
       metaclass (~> 0.0.1)
     rake (10.2.2)
+    subprocess (1.0.0)
 
 PLATFORMS
   ruby
@@ -30,3 +31,4 @@ DEPENDENCIES
   minitest (>= 5.2.3)
   mocha
   rake
+  subprocess
diff --git a/configatron.gemspec b/configatron.gemspec
index 097dfe1..2fca462 100755
--- a/configatron.gemspec
+++ b/configatron.gemspec
@@ -20,5 +20,6 @@ Gem::Specification.new do |gem|
 
   gem.add_development_dependency "rake"
   gem.add_development_dependency "mocha"
+  gem.add_development_dependency "subprocess"
   gem.add_development_dependency "minitest", '>=5.2.3'
 end
diff --git a/lib/configatron.rb b/lib/configatron.rb
index 5788eb9..3bfa807 100755
--- a/lib/configatron.rb
+++ b/lib/configatron.rb
@@ -3,7 +3,7 @@
 
 require 'configatron/deep_clone'
 require 'configatron/errors'
-require 'configatron/kernel'
+require 'configatron/kernel_store'
 require 'configatron/store'
 
 # Proc *must* load before dynamic/delayed, or else Configatron::Proc
@@ -14,3 +14,11 @@
 
 class Configatron
 end
+
+# NO_EXT gets defined when you require "configatron/core", which
+# signals that you don't want any extensions. It'd be nice to have a
+# better internal signaling mechanism (could use environment
+# variables, but then they become part of the public interface).
+unless defined?(Configatron::NO_EXT)
+  require 'configatron/ext/kernel'
+end
diff --git a/lib/configatron/core.rb b/lib/configatron/core.rb
index 67dcf2e..e6ebbb0 100644
--- a/lib/configatron/core.rb
+++ b/lib/configatron/core.rb
@@ -1,2 +1,6 @@
-$stderr.puts "Warning: Loading 'configatron/core' has been deprecated. Please just load 'configatron directly."
+class Configatron
+  # Signals that we should not load the extensions.
+  NO_EXT = true
+end
+
 require 'configatron'
diff --git a/lib/configatron/ext/kernel.rb b/lib/configatron/ext/kernel.rb
new file mode 100644
index 0000000..b878873
--- /dev/null
+++ b/lib/configatron/ext/kernel.rb
@@ -0,0 +1,5 @@
+module Kernel
+  def configatron
+    Configatron::KernelStore.instance
+  end
+end
diff --git a/lib/configatron/kernel.rb b/lib/configatron/kernel_store.rb
similarity index 91%
rename from lib/configatron/kernel.rb
rename to lib/configatron/kernel_store.rb
index 3ce215b..bb604b0 100644
--- a/lib/configatron/kernel.rb
+++ b/lib/configatron/kernel_store.rb
@@ -50,9 +50,3 @@ def unlock!
     @locked = false
   end
 end
-
-module Kernel
-  def configatron
-    Configatron::KernelStore.instance
-  end
-end
diff --git a/test/functional/_lib/scripts/core.rb b/test/functional/_lib/scripts/core.rb
new file mode 100755
index 0000000..2c5178d
--- /dev/null
+++ b/test/functional/_lib/scripts/core.rb
@@ -0,0 +1,11 @@
+#!/usr/bin/env ruby
+
+if defined?(configatron)
+  raise "`configatron` method was defined at load-time!"
+end
+
+require 'configatron/core'
+
+if defined?(configatron)
+  raise "Loaded configatron/core but `configatron` was defined!"
+end
diff --git a/test/functional/loading.rb b/test/functional/loading.rb
new file mode 100644
index 0000000..5b2e16a
--- /dev/null
+++ b/test/functional/loading.rb
@@ -0,0 +1,10 @@
+require_relative '_lib'
+require 'subprocess'
+
+class Critic::Functional::ConfigatronTest < Critic::Functional::Test
+  describe 'loading' do
+    it 'does not define top-level configatron method if loading configatron/core' do
+      Subprocess.check_call([File.expand_path('../_lib/scripts/core.rb', __FILE__)])
+    end
+  end
+end
diff --git a/test/unit/configatron/kernel.rb b/test/unit/configatron/kernel_store.rb
similarity index 100%
rename from test/unit/configatron/kernel.rb
rename to test/unit/configatron/kernel_store.rb