diff --git a/modules/ui.scm b/modules/ui.scm
index 1168642..d6f120b 100644
--- a/modules/ui.scm
+++ b/modules/ui.scm
@@ -12,8 +12,12 @@
 	(srfi 4)
 	(srfi 99))
 
+;; The main font for the game.
 (define base-font (font "../res/fonts/Felipa-Regular.ttf"))
 
+;; Label is a generic text container.
+;; Centered? here is a pair of booleans, basically
+;; a mask saying which axis to center.
 (define-record-type <label>
   (int:make-label position centered? layer font font-size color text)
   label?
@@ -25,6 +29,7 @@
   (color label-color set-label-color!)
   (text label-text set-label-text!))
 
+;; Title/subtitle/footer etc are basically just different styles
 (export title)
 (define (title position text
 	       #!key
@@ -55,6 +60,7 @@
 		(color (make-color 0 0 0 1)))
   (int:make-label position centered layer font size color text))
 
+;; This needs to be added to actually draw entities with labels
 (export draw-labels)
 (define draw-labels
   (make-system
@@ -96,6 +102,8 @@
 	   (label-color label)
 	   (label-font label))))))))
 
+;; Button container
+;; state is in '(ready hovered clicked)
 (define-record-type <button>
   (int:make-button position size layer label state click-fn colors)
   button?
@@ -107,6 +115,7 @@
   (click-fn button-click-fn set-button-click-fn!)
   (colors button-colors set-button-colors!))
 
+;; Shortcut for making a button
 (export button)
 (define (button position label click-fn
 		#!key
@@ -117,6 +126,7 @@
 			      (make-color 0.39 0.39 0.39 1))))
   (int:make-button position size layer label 'ready click-fn colors))
 
+;; Helper function for updating the button state
 (define (check-button-state button)
   (let ((x-range (cons (v-x (button-pos button))
 		       (+ (v-x (button-pos button))
@@ -125,6 +135,7 @@
 		       (+ (v-y (button-pos button))
 			  (v-y (button-size button)))))
 	(mouse-pos (cons (get-mouse-x) (get-mouse-y))))
+    ;; Is the mouse in the rect drawn by x-range and y-range?
     (if (and (< (car x-range) (car mouse-pos) (cdr x-range))
 	     (< (car y-range) (cdr mouse-pos) (cdr y-range)))
 	(if (peek-event 'input 'click)
@@ -132,6 +143,7 @@
 	    (set-button-state! button 'hovered))
 	(set-button-state! button 'ready))))
 
+;; Helper function to render the button and its text
 (define (draw-button button)
   (push-render-object
    'screen
@@ -149,12 +161,14 @@
       #t
       1)))
   (let* ((txt (button-label button))
+	 ;; Figure out the length of the text
 	 (text-length (f32vector->list
 		       (measure-text-ex
 			(resource-contents (label-font txt))
 			(label-text txt)
 			(label-size txt)
 			1)))
+	 ;; Determine a centre offset internal to the button
 	 (center-offset (vec (- (/ (v-x (button-size button))
 				   2)
 				(/ (car text-length)
@@ -165,7 +179,7 @@
 				   2)))))
     (push-render-object
      'screen
-     (+ 1 (button-layer button))
+     (+ 1 (button-layer button)) ;; always draw text above the button
      (lambda ()
        (draw-font-text-2d
 	(v+ (button-pos button)
@@ -175,16 +189,18 @@
 	(label-color txt)
 	(label-font txt))))))
 
+;; If button is clicked, exec button click func
 (define (do-button-callback button)
   (when (eqv? 'clicked (button-state button))
     ((button-click-fn button))))
 
+;; Needs to be added to do buttons
 (export handle-buttons)
 (define handle-buttons
   (make-system
    'handle-buttons
    10
-   'batch
+   'batch ;; batch because we check for events for every button
    '(<button>)
    (lambda (buttons)
      (for-each
@@ -194,5 +210,6 @@
 	  (draw-button button)
 	  (do-button-callback button)))
       buttons)
+     ;; At the end of the function, clear click events
      (pop-event 'input 'click))))
 )
diff --git a/src/main-menu.scm b/src/main-menu.scm
index bd1dcc7..8066077 100644
--- a/src/main-menu.scm
+++ b/src/main-menu.scm
@@ -47,16 +47,20 @@
      "By Jakub Nowak with Imugi+Raylib"
      centered: (cons #t #f)))
 
+   ;; Play button
    (entity
     (button
+     ;; Roughly centered.
+     ;; these are ugly, hardcoded values.
      (vec (- (/ (car (*window-size*))
 		2)
 	     50)
 	  (- (/ (car (*window-size*))
 		2)
 	     100))
+     ;; Nested footer text
      (footer
-      (vec 0 0)
+      (vec 0 0) ;; this vec doesn't matter, it's overwritten internally
       "Start Game!")
      play-callback))
    ))