diff --git a/go.mod b/go.mod
index 52dcb83..9f28862 100644
--- a/go.mod
+++ b/go.mod
@@ -4,7 +4,7 @@ go 1.21.1
 
 require (
 	github.com/gen2brain/raylib-go/raylib v0.0.0-20241215043839-7a899c5e3aae
-	weforge.xyz/Spitfire/SPM v0.0.2
+	weforge.xyz/Spitfire/SPM v0.1.2
 )
 
 require (
diff --git a/go.sum b/go.sum
index f0dfdb6..2640b76 100644
--- a/go.sum
+++ b/go.sum
@@ -17,5 +17,7 @@ gopkg.in/ini.v1 v1.67.0 h1:Dgnx+6+nfE+IfzjUEISNeydPJh9AXNNsWbGP9KzCsOA=
 gopkg.in/ini.v1 v1.67.0/go.mod h1:pNLf8WUiyNEtQjuu5G5vTm06TEv9tsIgeAvK8hOrP4k=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-weforge.xyz/Spitfire/SPM v0.0.2 h1:VU487KrwK1ldW7cMDGZgUcYPjtb8djG7glQlXg5Do3E=
-weforge.xyz/Spitfire/SPM v0.0.2/go.mod h1:LkLCJPROt/UW0Ntlbm1Vk8CpqpBscY0IScfT3PprsC4=
+weforge.xyz/Spitfire/SPM v0.1.1 h1:E3bJROvtW8CJNXdZTd0QW8cfxAr/zIxgKIVR7sMBwYg=
+weforge.xyz/Spitfire/SPM v0.1.1/go.mod h1:LkLCJPROt/UW0Ntlbm1Vk8CpqpBscY0IScfT3PprsC4=
+weforge.xyz/Spitfire/SPM v0.1.2 h1:jY3WvRV5WFE9spne1YFGQNPOnnZqAxnZaa3l57pTigw=
+weforge.xyz/Spitfire/SPM v0.1.2/go.mod h1:LkLCJPROt/UW0Ntlbm1Vk8CpqpBscY0IScfT3PprsC4=
diff --git a/installer.go b/installer.go
index 0cb16f9..b035b18 100644
--- a/installer.go
+++ b/installer.go
@@ -1,3 +1,5 @@
+//go:build !windows
+
 package main
 
 import (
@@ -62,8 +64,8 @@ func (inst *Installer) StartDownloadDecompress() {
 		}
 
 		spm.UpdateProgress(0, "Downloading specified packages...")
-		if err := spm.AutoDownloadSpecified(specs); err != nil {
-			fmt.Println("AutoDownloadSpecifiedPackages failed:", err)
+		if err := spm.DownloadSpecified(specs); err != nil {
+			fmt.Println("DownloadSpecifiedPackages failed:", err)
 			inst.LastError = err
 			return
 		}
@@ -93,7 +95,7 @@ func (inst *Installer) FinalInstall() {
 	inst.doFinalInstall()
 }
 
-// doFinalInstall does the actual installation by invoking AutoInstallUpdates.
+// doFinalInstall does the actual installation by invoking InstallUpdates.
 func (inst *Installer) doFinalInstall() {
 	inst.IsInstalling = true
 	inst.PendingInstall = false // we are fulfilling the install now
@@ -105,14 +107,7 @@ func (inst *Installer) doFinalInstall() {
 		}()
 
 		spm.UpdateProgress(0, "Installing updates...")
-		if err := spm.AutoInstallUpdates(); err != nil {
-			inst.LastError = err
-			return
-		}
-
-		// Register the app in Windows (i.e. create registry entries)
-		spm.UpdateProgress(0, "Registering app...")
-		if err := spm.RegisterApp(); err != nil {
+		if err := spm.InstallUpdates(); err != nil {
 			inst.LastError = err
 			return
 		}
diff --git a/installer_win.go b/installer_win.go
new file mode 100644
index 0000000..e7e24e3
--- /dev/null
+++ b/installer_win.go
@@ -0,0 +1,130 @@
+//go:build windows
+
+package main
+
+import (
+	"fmt"
+	"runtime"
+
+	spm "weforge.xyz/Spitfire/SPM"
+)
+
+// Installer manages the download, decompression, and installation processes.
+type Installer struct {
+	// Progress info from SPM
+	Progress int
+	Task     string
+
+	// Internal states
+	IsDownloading  bool
+	IsInstalling   bool
+	DoneDownload   bool
+	DoneInstall    bool
+	LastError      error
+	PendingInstall bool
+}
+
+// NewInstaller creates a new Installer with initial state.
+func NewInstaller() *Installer {
+	return &Installer{}
+}
+
+// StartDownloadDecompress starts the download and decompression in a background goroutine.
+func (inst *Installer) StartDownloadDecompress() {
+	inst.IsDownloading = true
+	go func() {
+		defer func() {
+			inst.IsDownloading = false
+			// Signal that download phase is complete.
+			inst.DoneDownload = (inst.LastError == nil)
+			// If a final install was requested, go ahead.
+			if inst.PendingInstall && inst.DoneDownload && !inst.IsInstalling && !inst.DoneInstall {
+				inst.doFinalInstall()
+			}
+		}()
+
+		spm.UpdateProgress(0, "Preparing to download...")
+
+		// Define the package specifications.
+		specs := []spm.AppIndexEntry{
+			{
+				Name:    "spitfire-luncher",
+				Release: "nightly",
+				OS:      "windows",
+				Arch:    runtime.GOARCH,
+				Type:    "luncher",
+			},
+			{
+				Name:    "spitfire-browser",
+				Release: "nightly",
+				OS:      "windows",
+				Arch:    runtime.GOARCH,
+				Type:    "browser",
+			},
+		}
+
+		spm.UpdateProgress(0, "Downloading specified packages...")
+		if err := spm.DownloadSpecified(specs); err != nil {
+			fmt.Println("DownloadSpecifiedPackages failed:", err)
+			inst.LastError = err
+			return
+		}
+
+		spm.UpdateProgress(0, "Download and decompression complete!")
+		// Here, update your installer state so FinalInstall() can proceed.
+		inst.DoneDownload = true
+	}()
+}
+
+// FinalInstall is called by the UI to request installation.
+// If download is done, it runs immediately, otherwise sets PendingInstall=true.
+func (inst *Installer) FinalInstall() {
+	// Already installed or installing => ignore repeated calls.
+	if inst.IsInstalling || inst.DoneInstall {
+		return
+	}
+
+	// If not done downloading, mark that we want to install once finished.
+	if !inst.DoneDownload {
+		fmt.Println("Cannot install now: download and decompression not complete -> pending install.")
+		inst.PendingInstall = true
+		return
+	}
+
+	// Otherwise, go ahead and install now.
+	inst.doFinalInstall()
+}
+
+// doFinalInstall does the actual installation by invoking InstallUpdates.
+func (inst *Installer) doFinalInstall() {
+	inst.IsInstalling = true
+	inst.PendingInstall = false // we are fulfilling the install now
+
+	go func() {
+		defer func() {
+			inst.IsInstalling = false
+			inst.DoneInstall = (inst.LastError == nil)
+		}()
+
+		spm.UpdateProgress(0, "Installing updates...")
+		if err := spm.InstallUpdates(); err != nil {
+			inst.LastError = err
+			return
+		}
+
+		// Register the app in Windows (i.e. create registry entries)
+		spm.UpdateProgress(0, "Registering app...")
+		if err := spm.RegisterApp(); err != nil {
+			inst.LastError = err
+			return
+		}
+
+		spm.UpdateProgress(100, "Installation complete!")
+	}()
+}
+
+// PollProgress fetches the latest progress and task from SPM.
+func (inst *Installer) PollProgress() {
+	p, t := spm.GetProgress()
+	inst.Progress, inst.Task = p, t
+}