diff --git a/lua/lazy/core/plugin.lua b/lua/lazy/core/plugin.lua
index 3825960..ccc2745 100644
--- a/lua/lazy/core/plugin.lua
+++ b/lua/lazy/core/plugin.lua
@@ -6,6 +6,9 @@ local Cache = require("lazy.core.cache")
 ---@class LazyCorePlugin
 local M = {}
 
+local list_merge = { "dependencies" }
+vim.list_extend(list_merge, vim.tbl_values(Handler.types))
+
 ---@class LazySpecLoader
 ---@field plugins table<string, LazyPlugin>
 ---@field disabled table<string, LazyPlugin>
@@ -99,6 +102,7 @@ function Spec:add(plugin, results, is_dep)
     self.plugins[plugin.name] = plugin
     return results and table.insert(results, plugin.name)
   else
+    -- FIXME: we should somehow merge when needed
     plugin._.kind = "disabled"
     self.disabled[plugin.name] = plugin
     self.plugins[plugin.name] = nil
@@ -198,36 +202,29 @@ end
 ---@param new LazyPlugin
 ---@return LazyPlugin
 function Spec:merge(old, new)
-  local is_dep = old._.dep and new._.dep
+  new._.dep = old._.dep and new._.dep
 
-  ---@diagnostic disable-next-line: no-unknown
-  for k, v in pairs(new) do
-    if k == "_" then
-    elseif old[k] ~= nil and old[k] ~= v then
-      if Handler.types[k] then
-        local values = type(v) == "string" and { v } or v
-        vim.list_extend(values, type(old[k]) == "string" and { old[k] } or old[k])
-        ---@diagnostic disable-next-line: no-unknown
-        old[k] = values
-      elseif k == "config" or k == "priority" then
-        old[k] = v
-      elseif k == "dependencies" then
-        for _, dep in ipairs(v) do
-          if not vim.tbl_contains(old[k], dep) then
-            table.insert(old[k], dep)
-          end
-        end
-      else
-        old[k] = v
-        self:warn("Overwriting key `" .. k .. "`\n" .. vim.inspect({ old = old, new = new }))
-      end
-    else
+  for _, prop in ipairs(list_merge) do
+    if new[prop] and old[prop] then
+      ---@type any[]
+      local props = {}
       ---@diagnostic disable-next-line: no-unknown
-      old[k] = v
+      for _, value in ipairs(old[prop]) do
+        props[#props + 1] = value
+      end
+      ---@diagnostic disable-next-line: no-unknown
+      for _, value in ipairs(new[prop]) do
+        if not vim.tbl_contains(props, value) then
+          props[#props + 1] = value
+        end
+      end
+      ---@diagnostic disable-next-line: no-unknown
+      new[prop] = props
     end
   end
-  old._.dep = is_dep
-  return old
+  new._.super = old
+  setmetatable(new, { __index = old })
+  return new
 end
 
 function M.update_state()
diff --git a/lua/lazy/health.lua b/lua/lazy/health.lua
index 7b8fe8a..24b9de2 100644
--- a/lua/lazy/health.lua
+++ b/lua/lazy/health.lua
@@ -31,41 +31,10 @@ function M.check()
     vim.health.report_ok("packer_compiled.lua not found")
   end
 
-  local valid = {
-    1,
-    "name",
-    "url",
-    "enabled",
-    "lazy",
-    "dev",
-    "dependencies",
-    "init",
-    "config",
-    "build",
-    "branch",
-    "tag",
-    "commit",
-    "version",
-    "module",
-    "pin",
-    "cmd",
-    "event",
-    "keys",
-    "ft",
-    "dir",
-    "priority",
-    "cond",
-    "_",
-  }
   local spec = Config.spec
   for _, plugin in pairs(spec.plugins) do
-    for key in pairs(plugin) do
-      if not vim.tbl_contains(valid, key) then
-        if key ~= "module" or type(plugin.module) ~= "boolean" then
-          vim.health.report_warn("{" .. plugin.name .. "}: unknown key <" .. key .. ">")
-        end
-      end
-    end
+    M.check_valid(plugin)
+    M.check_override(plugin)
   end
   if #spec.notifs > 0 then
     vim.health.report_error("Issues were reported when loading your specs:")
@@ -82,4 +51,55 @@ function M.check()
   end
 end
 
+---@param plugin LazyPlugin
+function M.check_valid(plugin)
+  for key in pairs(plugin) do
+    if not vim.tbl_contains(M.valid, key) then
+      if key ~= "module" or type(plugin.module) ~= "boolean" then
+        vim.health.report_warn("{" .. plugin.name .. "}: unknown key <" .. key .. ">")
+      end
+    end
+  end
+end
+
+---@param plugin LazyPlugin
+function M.check_override(plugin)
+  if not plugin._.super then
+    return
+  end
+
+  for key, value in pairs(plugin._.super) do
+    if key ~= "_" and plugin[key] and plugin[key] ~= value then
+      vim.health.report_warn("{" .. plugin.name .. "}: overriding <" .. key .. ">")
+    end
+  end
+end
+
+M.valid = {
+  1,
+  "name",
+  "url",
+  "enabled",
+  "lazy",
+  "dev",
+  "dependencies",
+  "init",
+  "config",
+  "build",
+  "branch",
+  "tag",
+  "commit",
+  "version",
+  "module",
+  "pin",
+  "cmd",
+  "event",
+  "keys",
+  "ft",
+  "dir",
+  "priority",
+  "cond",
+  "_",
+}
+
 return M
diff --git a/lua/lazy/types.lua b/lua/lazy/types.lua
index c461c4c..ab3832f 100644
--- a/lua/lazy/types.lua
+++ b/lua/lazy/types.lua
@@ -13,6 +13,7 @@
 ---@field kind? LazyPluginKind
 ---@field dep? boolean True if this plugin is only in the spec as a dependency
 ---@field cond? boolean
+---@field super? LazyPlugin
 
 ---@class LazyPluginHooks
 ---@field init? fun(LazyPlugin) Will always be run