Forgot to delciare the emulation nix file.

nodes/hosts/common/configuration.nix

@@ -2,6 +2,7 @@
 {
   imports = [
     inputs.nix-flatpak.nixosModules.nix-flatpak
+    ./programs/emulation.nix
     ./programs/firefox.nix
     ./programs/gaming.nix
     ./programs/general.nix

nodes/hosts/common/programs/emulation.nix

@@ -0,0 +1,17 @@
+{ pkgs, inputs, ... }: {
+  # List packages installed in system profile. To search, run:
+  # $ nix search wget
+  environment.systemPackages = [
+    pkgs.ppsspp
+    #pkgs.ppsspp-sdl-wayland
+    pkgs.quickemu
+    #pkgs.retroarch-full
+    # Broken
+    #inputs.suyu.packages.${pkgs.system}.suyu
+  ];
+
+  services.flatpak.packages = [
+    "io.github.ryubing.Ryujinx"
+  ];
+}
+