diff --git a/src/mame/drivers/namcos22.c b/src/mame/drivers/namcos22.c
index be4486b9c19..45e1a9d0795 100644
--- a/src/mame/drivers/namcos22.c
+++ b/src/mame/drivers/namcos22.c
@@ -2444,11 +2444,11 @@ static WRITE32_HANDLER( namcos22_mcuram_w )
 }
 
 /**
- * I don't know how "SPOT RAM" affects the display, yet.
- * I believe it's to support a "spotlight" effect, orthogonal to the polygon layer.
+ * Spot RAM affects how the text layer is blended with the scene, it is not yet known exactly how.
  * It isn't directly memory mapped, but rather ports are used to populate and poll it.
  *
  * See Time Crisis "SPOT RAM" self test for sample use.
+ * It is also used in Dirt Dash night section.
  */
 #define SPOTRAM_SIZE (320*4)
 
diff --git a/src/mame/video/namcos22.c b/src/mame/video/namcos22.c
index 449298d331f..d52c8669c4d 100644
--- a/src/mame/video/namcos22.c
+++ b/src/mame/video/namcos22.c
@@ -179,7 +179,7 @@ UpdateVideoMixer( running_machine &machine )
     16,17,18        global fade rgb
     19              global fade factor
     1a              fade target flags
-    1b              textlayer palette base?
+    1b              textlayer palette base
     1c
     1d
     1e
@@ -624,7 +624,7 @@ static void poly3d_DrawQuad(running_machine &machine, bitmap_t *bitmap, int text
 
         */
 
-		/*  czattr:
+		/*  czattr: - assumed that it's write-only
                0    2    4    6    8    a    c    e
             ^^^^ ^^^^ ^^^^ ^^^^                        cz offset, signed16 per cztype 0,1,2,3
                                 ^^^^                   flags, nybble per cztype 3,2,1,0 - 4 probably means enable