diff --git a/polymer/eduke32/source/lunatic/defs.ilua b/polymer/eduke32/source/lunatic/defs.ilua
index ff42d35da..9f07729c3 100644
--- a/polymer/eduke32/source/lunatic/defs.ilua
+++ b/polymer/eduke32/source/lunatic/defs.ilua
@@ -1477,6 +1477,13 @@ local function our_require(modname, ...)
 
     --- Search user modules...
 
+    if (modname:find("[/\\]")) then
+        error("Module name must not contain directory separators", ERRLEV-1)
+    end
+    -- Instead, dots are translated to directory separators. For EDuke32's
+    -- virtual file system, this is always a forward slash.
+    modname = modname:gsub("%.", "/")
+
     local omod = package_loaded[modname]
     if (omod ~= nil) then
         if (omod==false) then
@@ -2038,8 +2045,16 @@ end
 if (not g_firstRun) then
     local i=0
     while (ffiC.g_elModules[i] ~= nil) do
-        local modname = ffi.string(ffiC.g_elModules[i])
-        our_require((modname:gsub("%.lua$","")))
+        -- Get the module name and strip the trailing extension.
+        local modname = ffi.string(ffiC.g_elModules[i]):gsub("%.lua$","")
+
+        if (modname:find("%.")) then
+            -- Because they will be replaced by dirseps in our_require().
+            error("Dots are not permitted in module names", 0)
+        end
+        -- Allow forward slashes in module names from the cmdline.
+        our_require((modname:gsub("%.lua$",""):gsub("/",".")))
+
         i = i+1
     end
 end
diff --git a/polymer/eduke32/source/lunatic/test.elua b/polymer/eduke32/source/lunatic/test.elua
index 1f4efb804..658f23423 100644
--- a/polymer/eduke32/source/lunatic/test.elua
+++ b/polymer/eduke32/source/lunatic/test.elua
@@ -180,7 +180,7 @@ checkfail('local spr = sprite[0]; local x=spr+1', "attempt to perform arithmetic
 
 checkfail('gameactor(1680, 0)', "invalid last argument to gameactor: must be a function")
 
-checkfail("do local bt=require'test/test_bitar'; bt.QWE=1; end", "modifying module table forbidden")
+checkfail("do local bt=require'test.test_bitar'; bt.QWE=1; end", "modifying module table forbidden")
 -- the cdata returned by player[] can't be made into a pointer!
 checkfail("do local pl=player[0]; i=pl[1]; end")
 checkfail("do local ud=gv.ud.camerasprite; end", "access forbidden")  -- test for proper decl()
@@ -470,11 +470,11 @@ end)
 
 printf("EVENT_INIT = %d", gv.EVENT_INIT)  -- tests default defines
 
-local bittest = require "test/test_bitar"
+local bittest = require "test.test_bitar"
 bittest.sieve()
 
-require("test/test_geom")
-require("test/test_rotspr")
+require("test.test_geom")
+require("test.test_rotspr")
 
 do
     -- Test ksin vs. sinb