diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9e23584..250e448 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,17 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
+## [0.3.1] 2025-05-30
+
+### Added
+
+- Add VIM (i.e. `hjkl`) navigation support.
+
+### Fixed
+
+- Add parameter validation and mandatory to ensure commands don't fail
+  unexpectedly.
+
 ## [0.3.0] 2025-05-29
 
 ### Added
diff --git a/PesterExplorer/PesterExplorer.psd1 b/PesterExplorer/PesterExplorer.psd1
index 59e550a..0e03106 100644
--- a/PesterExplorer/PesterExplorer.psd1
+++ b/PesterExplorer/PesterExplorer.psd1
@@ -12,7 +12,7 @@
     RootModule = 'PesterExplorer.psm1'
 
     # Version number of this module.
-    ModuleVersion = '0.3.0'
+    ModuleVersion = '0.3.1'
 
     # Supported PSEditions
     # CompatiblePSEditions = @()
diff --git a/PesterExplorer/Private/Get-ShortcutKeyPanel.ps1 b/PesterExplorer/Private/Get-ShortcutKeyPanel.ps1
index 24942e9..a462244 100644
--- a/PesterExplorer/Private/Get-ShortcutKeyPanel.ps1
+++ b/PesterExplorer/Private/Get-ShortcutKeyPanel.ps1
@@ -20,11 +20,11 @@ function Get-ShortcutKeyPanel {
     #>
     [CmdletBinding()]
     $shortcutKeys = @(
-        "Up, Down - Navigate",
+        "Up/J, Down/K - Navigate",
         "Home, End - Jump to Top/Bottom",
         "PageUp, PageDown - Scroll",
-        "Enter - Explore",
-        "Tab - Switch Panel",
+        "Enter - Explore Item",
+        "Tab, Left/H, Right/L - Switch Panel",
         "Esc - Back",
         "Ctrl+C - Exit"
     )
diff --git a/PesterExplorer/Public/Show-PesterResult.ps1 b/PesterExplorer/Public/Show-PesterResult.ps1
index 36f6244..759e19c 100644
--- a/PesterExplorer/Public/Show-PesterResult.ps1
+++ b/PesterExplorer/Public/Show-PesterResult.ps1
@@ -27,6 +27,7 @@ function Show-PesterResult {
         Justification='This is actually used in the script block.'
     )]
     param (
+        [Parameter(Mandatory = $true)]
         [ValidateNotNullOrEmpty()]
         [Pester.Run]
         $PesterResult,
@@ -89,14 +90,13 @@ function Show-PesterResult {
 
             # Handle input
             $lastKeyPressed = Get-LastKeyPressed
-            # ToDo: Add vim navigation keys
             if ($null -ne $lastKeyPressed) {
                 #region List Navigation
                 if($selectedPane -eq 'list') {
-                    if ($lastKeyPressed.Key -eq "DownArrow") {
+                    if ($lastKeyPressed.Key -in @("j", "DownArrow")) {
                         $selectedItem = $list[($list.IndexOf($selectedItem) + 1) % $list.Count]
                         $scrollPosition = 0
-                    } elseif ($lastKeyPressed.Key -eq "UpArrow") {
+                    } elseif ($lastKeyPressed.Key -in @("k", "UpArrow")) {
                         $selectedItem = $list[($list.IndexOf($selectedItem) - 1 + $list.Count) % $list.Count]
                         $scrollPosition = 0
                     } elseif ($lastKeyPressed.Key -eq "PageDown") {
@@ -115,7 +115,7 @@ function Show-PesterResult {
                     } elseif ($lastKeyPressed.Key -eq "End") {
                         $selectedItem = $list[-1]
                         $scrollPosition = 0
-                    } elseif ($lastKeyPressed.Key -in @("Tab", "RightArrow")) {
+                    } elseif ($lastKeyPressed.Key -in @("Tab", "RightArrow", "l")) {
                         $selectedPane = 'preview'
                     } elseif ($lastKeyPressed.Key -eq "Enter") {
                         <# Recurse into Pester Object #>
@@ -150,8 +150,7 @@ function Show-PesterResult {
                 }
                 else {
                     #region Preview Navigation
-                    # ToDo: Add support for scrolling the right panel
-                    if ($lastKeyPressed.Key -in "Escape", "Tab", "LeftArrow", "RightArrow") {
+                    if ($lastKeyPressed.Key -in "Escape", "Tab", "LeftArrow", "h") {
                         $selectedPane = 'list'
                     } elseif ($lastKeyPressed.Key -eq "Down") {
                         # Scroll down in the preview panel
@@ -172,8 +171,22 @@ function Show-PesterResult {
 
             # Generate new data
             $titlePanel = Get-TitlePanel -Item $object
-            $listPanel = Get-ListPanel -List $list -SelectedItem $selectedItem -SelectedPane $selectedPane
-            $previewPanel = Get-PreviewPanel -Items $items -SelectedItem $selectedItem -ScrollPosition $scrollPosition -PreviewHeight $previewHeight -PreviewWidth $previewWidth -SelectedPane $selectedPane
+            $getListPanelSplat = @{
+                List = $list
+                SelectedItem = $selectedItem
+                SelectedPane = $selectedPane
+            }
+            $listPanel = Get-ListPanel @getListPanelSplat
+
+            $getPreviewPanelSplat = @{
+                Items = $items
+                SelectedItem = $selectedItem
+                ScrollPosition = $scrollPosition
+                PreviewHeight = $previewHeight
+                PreviewWidth = $previewWidth
+                SelectedPane = $selectedPane
+            }
+            $previewPanel = Get-PreviewPanel @getPreviewPanelSplat
 
             # Update layout
             $layout["header"].Update($titlePanel) | Out-Null
diff --git a/PesterExplorer/Public/Show-PesterResultTree.ps1 b/PesterExplorer/Public/Show-PesterResultTree.ps1
index 57657d5..8feda02 100644
--- a/PesterExplorer/Public/Show-PesterResultTree.ps1
+++ b/PesterExplorer/Public/Show-PesterResultTree.ps1
@@ -20,6 +20,8 @@ function Show-PesterResultTree {
     [CmdletBinding()]
     [OutputType([void])]
     param (
+        [Parameter(Mandatory = $true)]
+        [ValidateNotNullOrEmpty()]
         [Pester.Run]
         $PesterResult
     )
diff --git a/docs/en-US/Show-PesterResult.md b/docs/en-US/Show-PesterResult.md
index 02aab3a..fc9fc82 100644
--- a/docs/en-US/Show-PesterResult.md
+++ b/docs/en-US/Show-PesterResult.md
@@ -13,7 +13,7 @@ Open a TUI to explore the Pester result object.
 ## SYNTAX
 
 ```
-Show-PesterResult [[-PesterResult] <Run>] [-NoShortcutPanel] [-ProgressAction <ActionPreference>]
+Show-PesterResult [-PesterResult] <Run> [-NoShortcutPanel] [-ProgressAction <ActionPreference>]
  [<CommonParameters>]
 ```
 
@@ -42,7 +42,7 @@ Type: Run
 Parameter Sets: (All)
 Aliases:
 
-Required: False
+Required: True
 Position: 1
 Default value: None
 Accept pipeline input: False
diff --git a/docs/en-US/Show-PesterResultTree.md b/docs/en-US/Show-PesterResultTree.md
index cbf270f..4060296 100644
--- a/docs/en-US/Show-PesterResultTree.md
+++ b/docs/en-US/Show-PesterResultTree.md
@@ -13,7 +13,7 @@ Show a Pester result in a tree format using Spectre.Console.
 ## SYNTAX
 
 ```
-Show-PesterResultTree [[-PesterResult] <Run>] [-ProgressAction <ActionPreference>] [<CommonParameters>]
+Show-PesterResultTree [-PesterResult] <Run> [-ProgressAction <ActionPreference>] [<CommonParameters>]
 ```
 
 ## DESCRIPTION
@@ -43,7 +43,7 @@ Type: Run
 Parameter Sets: (All)
 Aliases:
 
-Required: False
+Required: True
 Position: 1
 Default value: None
 Accept pipeline input: False