diff --git a/configs/config.yaml b/configs/config.yaml
index 1fe38937..52a5475c 100644
--- a/configs/config.yaml
+++ b/configs/config.yaml
@@ -125,10 +125,19 @@ emulator:
           compression: zip
       # Libretro core configuration
       #
+      # The emulator selection will happen in this order:
+      #   - based on the folder name in the folder param
+      #   - based on the folder name (core name) in the list (i.e. nes, snes)
+      #   - based on the rom names in the roms param
+      #
       # Available config params:
       #   - lib (string)
       #   - config (string)
       #   - roms ([]string)
+      #   - folder (string)
+      #       By default emulator selection is based on the folder named as cores
+      #       in the list (i.e. nes, snes) but if you specify folder param,
+      #       then it will try to load the ROM file from that folder first.
       #   - width (int) -- broken
       #   - height (int) -- broken
       #   - ratio (float)
@@ -142,11 +151,16 @@ emulator:
         pcsx:
           lib: pcsx_rearmed_libretro
           roms: [ "cue" ]
+          # example of folder override
+          folder: psx
         # MAME core requires additional manual setup, please read:
         # https://docs.libretro.com/library/fbneo/
         mame:
           lib: fbneo_libretro
           roms: [ "zip" ]
+        mame2003:
+          lib: mame2003_libretro
+          roms: [ "zip" ]
         nes:
           lib: nestopia_libretro
           roms: [ "nes" ]
diff --git a/pkg/config/emulator/config.go b/pkg/config/emulator/config.go
index 0b2af352..35cf870e 100644
--- a/pkg/config/emulator/config.go
+++ b/pkg/config/emulator/config.go
@@ -3,6 +3,7 @@ package emulator
 import (
 	"path"
 	"path/filepath"
+	"strings"
 )
 
 type Emulator struct {
@@ -42,6 +43,7 @@ type LibretroCoreConfig struct {
 	Lib         string
 	Config      string
 	Roms        []string
+	Folder      string
 	Width       int
 	Height      int
 	Ratio       float64
@@ -64,17 +66,24 @@ func (e Emulator) GetLibretroCoreConfig(emulator string) LibretroCoreConfig {
 	return conf
 }
 
-// GetEmulatorByRom returns emulator name by its supported ROM name.
-// !to cache into an optimized data structure
-func (e Emulator) GetEmulatorByRom(rom string) string {
+// GetEmulator tries to find a suitable emulator.
+// !to remove quadratic complexity
+func (e Emulator) GetEmulator(rom string, path string) string {
+	found := ""
 	for emu, core := range e.Libretro.Cores.List {
 		for _, romName := range core.Roms {
 			if rom == romName {
-				return emu
+				found = emu
+				if p := strings.SplitN(filepath.ToSlash(path), "/", 2); len(p) > 1 {
+					folder := p[0]
+					if (folder != "" && folder == core.Folder) || folder == emu {
+						return emu
+					}
+				}
 			}
 		}
 	}
-	return ""
+	return found
 }
 
 func (e Emulator) GetSupportedExtensions() []string {
diff --git a/pkg/config/emulator/config_test.go b/pkg/config/emulator/config_test.go
new file mode 100644
index 00000000..ebef77c2
--- /dev/null
+++ b/pkg/config/emulator/config_test.go
@@ -0,0 +1,52 @@
+package emulator
+
+import "testing"
+
+func TestGetEmulator(t *testing.T) {
+	tests := []struct {
+		rom      string
+		path     string
+		config   map[string]LibretroCoreConfig
+		emulator string
+	}{
+		{
+			rom:  "nes",
+			path: "test/game.nes",
+			config: map[string]LibretroCoreConfig{
+				"snes": {Roms: []string{"nes"}},
+				"nes":  {Folder: "test", Roms: []string{"nes"}},
+			},
+			emulator: "nes",
+		},
+		{
+			rom:  "nes",
+			path: "nes/game.nes",
+			config: map[string]LibretroCoreConfig{
+				"snes": {Roms: []string{"nes"}},
+				"nes":  {Roms: []string{"nes"}},
+			},
+			emulator: "nes",
+		},
+		{
+			rom:  "nes",
+			path: "test/game.nes",
+			config: map[string]LibretroCoreConfig{
+				"snes": {Roms: []string{"nes"}},
+				"nes":  {Roms: []string{"nes"}},
+			},
+			emulator: "nes",
+		},
+	}
+
+	emu := Emulator{
+		Libretro: LibretroConfig{},
+	}
+
+	for _, test := range tests {
+		emu.Libretro.Cores.List = test.config
+		em := emu.GetEmulator(test.rom, test.path)
+		if test.emulator != em {
+			t.Errorf("expected result: %v, but was %v with: %v, %v", test.emulator, em, test.rom, test.path)
+		}
+	}
+}
diff --git a/pkg/coordinator/useragenthandlers.go b/pkg/coordinator/useragenthandlers.go
index 3a120e71..fbbcb7b4 100644
--- a/pkg/coordinator/useragenthandlers.go
+++ b/pkg/coordinator/useragenthandlers.go
@@ -205,6 +205,7 @@ func newGameStartCall(roomId string, data string, library games.GameLibrary) (ap
 
 	return api.GameStartCall{
 		Name: gameInfo.Name,
+		Base: gameInfo.Base,
 		Path: gameInfo.Path,
 		Type: gameInfo.Type,
 	}, nil
diff --git a/pkg/cws/api/coordinator.go b/pkg/cws/api/coordinator.go
index 696e5223..2e5340fe 100644
--- a/pkg/cws/api/coordinator.go
+++ b/pkg/cws/api/coordinator.go
@@ -30,6 +30,7 @@ func (packet *GameStartRequest) From(data string) error { return from(packet, da
 
 type GameStartCall struct {
 	Name string `json:"name"`
+	Base string `json:"base"`
 	Path string `json:"path"`
 	Type string `json:"type"`
 }
diff --git a/pkg/games/game_library.go b/pkg/games/game_library.go
index 76046af9..dfd06228 100644
--- a/pkg/games/game_library.go
+++ b/pkg/games/game_library.go
@@ -74,6 +74,7 @@ type GameMetadata struct {
 	Name string
 	// the game file extension (e.g. nes, n64)
 	Type string
+	Base string
 	// the game path relative to the library base path
 	Path string
 }
@@ -126,8 +127,8 @@ func (lib *library) GetAll() []GameMetadata {
 func (lib *library) FindGameByName(name string) GameMetadata {
 	var game GameMetadata
 	if val, ok := lib.games[name]; ok {
-		val.Path = filepath.Join(lib.config.path, val.Path)
-		game = val
+		val.Base = lib.config.path
+		return val
 	}
 	return game
 }
diff --git a/pkg/games/game_library_test.go b/pkg/games/game_library_test.go
index d360abd2..638bc277 100644
--- a/pkg/games/game_library_test.go
+++ b/pkg/games/game_library_test.go
@@ -1,7 +1,6 @@
 package games
 
 import (
-	"reflect"
 	"testing"
 )
 
@@ -31,7 +30,19 @@ func TestLibraryScan(t *testing.T) {
 			return meta.Name
 		})
 
-		if !reflect.DeepEqual(test.expected, list) {
+		// ^2 complexity (;
+		all := true
+		for _, expect := range test.expected {
+			found := false
+			for _, game := range list {
+				if game == expect {
+					found = true
+					break
+				}
+			}
+			all = all && found
+		}
+		if !all {
 			t.Errorf("Test fail for dir %v with %v != %v", test.directory, list, test.expected)
 		}
 	}
diff --git a/pkg/worker/internalhandlers.go b/pkg/worker/internalhandlers.go
index 46cfe5bf..58755b3a 100644
--- a/pkg/worker/internalhandlers.go
+++ b/pkg/worker/internalhandlers.go
@@ -110,28 +110,21 @@ func (h *Handler) handleGameStart() cws.PacketHandler {
 		log.Println("Received a start request from coordinator")
 		session := h.getSession(resp.SessionID)
 		if session == nil {
-			log.Printf("Error: No session for ID: %s\n", resp.SessionID)
+			log.Printf("error: no session with id: %s", resp.SessionID)
 			return cws.EmptyPacket
 		}
 
-		peerconnection := session.peerconnection
 		// TODO: Standardize for all types of packet. Make WSPacket generic
-		startPacket := api.GameStartCall{}
-		if err := startPacket.From(resp.Data); err != nil {
+		rom := api.GameStartCall{}
+		if err := rom.From(resp.Data); err != nil {
 			return cws.EmptyPacket
 		}
-		gameMeta := games.GameMetadata{
-			Name: startPacket.Name,
-			Type: startPacket.Type,
-			Path: startPacket.Path,
-		}
-
-		room := h.startGameHandler(gameMeta, resp.RoomID, resp.PlayerIndex, peerconnection)
+		game := games.GameMetadata{Name: rom.Name, Type: rom.Type, Base: rom.Base, Path: rom.Path}
+		room := h.startGameHandler(game, resp.RoomID, resp.PlayerIndex, session.peerconnection)
 		session.RoomID = room.ID
-		// TODO: can data race
+		// TODO: can data race (and it does)
 		h.rooms[room.ID] = room
-
-		return cws.WSPacket{ID: "start", RoomID: room.ID}
+		return cws.WSPacket{ID: api.GameStart, RoomID: room.ID}
 	}
 }
 
diff --git a/pkg/worker/room/room.go b/pkg/worker/room/room.go
index 779b06b3..65039dc8 100644
--- a/pkg/worker/room/room.go
+++ b/pkg/worker/room/room.go
@@ -10,6 +10,7 @@ import (
 	"math"
 	"net"
 	"os"
+	"path/filepath"
 	"sync"
 
 	"github.com/giongto35/cloud-game/v2/pkg/config/worker"
@@ -157,8 +158,8 @@ func NewRoom(roomID string, game games.GameMetadata, onlineStorage *storage.Clie
 		// If not then load room or create room from local.
 		log.Printf("Room %s started. GameName: %s, WithGame: %t", roomID, game.Name, cfg.Encoder.WithoutGame)
 
-		// Spawn new emulator based on gameName and plug-in all channels
-		emuName := cfg.Emulator.GetEmulatorByRom(game.Type)
+		// Spawn new emulator and plug-in all channels
+		emuName := cfg.Emulator.GetEmulator(game.Type, game.Path)
 		libretroConfig := cfg.Emulator.GetLibretroCoreConfig(emuName)
 
 		if cfg.Encoder.WithoutGame {
@@ -176,7 +177,7 @@ func NewRoom(roomID string, game games.GameMetadata, onlineStorage *storage.Clie
 			room.audioChannel = audioChannel
 		}
 
-		gameMeta := room.director.LoadMeta(game.Path)
+		gameMeta := room.director.LoadMeta(filepath.Join(game.Base, game.Path))
 
 		// nwidth, nheight are the WebRTC output size
 		var nwidth, nheight int