diff --git a/.gitignore b/.gitignore
index c2717a01..52ef0725 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,10 +1,9 @@
 *~
 node_modules
 local
-release
-gen
-test/output
+./release
+./gen
+./test/output
 tests_output/
 .DS_Store
 tmp
-
diff --git a/doc/notes.txt b/doc/notes.txt
index bb4b8845..b5f5e640 100644
--- a/doc/notes.txt
+++ b/doc/notes.txt
@@ -190,6 +190,7 @@ TODO:
   https://8bitworkshop.com/v3.4.1/javatari.js/release/javatari/javatari.js
   (32:443651)	Safari	12.1.2
 - Safari: doesn't send good exception reasons ("undefined")
+  - probably XMLHttpRequest.timeout (https://github.com/getsentry/sentry-javascript/issues/2210)
 
 
 
diff --git a/presets/sms-sms-libcv/mode4test.c b/presets/sms-sms-libcv/mode4test.c
index f8970a0b..28ec4fa1 100644
--- a/presets/sms-sms-libcv/mode4test.c
+++ b/presets/sms-sms-libcv/mode4test.c
@@ -2,14 +2,19 @@
 #include <cv.h>
 #include <cvu.h>
 
+// SMS doesn't have a BIOS
+// so we have to link in a pattern table
+
 #ifdef CV_SMS
 //#link "fonts.s"
 extern uintptr_t font_bitmap_a[];
 extern uintptr_t font_bitmap_0[];
 #endif
 
+// HALT waits for a 60 Hz interrupt
 #define wait_vsync() __asm__("halt")
 
+// VRAM table addresses
 #define PATTERN		0x0000	// 256*8 = 2048 bytes
 #define IMAGE		0x2000	// 32*24 = 768 bytes
 #define COLOR		0x0b00	// 32 bytes
@@ -18,37 +23,39 @@ extern uintptr_t font_bitmap_0[];
 
 /*{pal:222,n:16}*/
 const char PALETTE0[16] = {
-  0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
-  0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x0D,
+  0x10, 0x03, 0x0B, 0x0F, 0x13, 0x17, 0x1B, 0x1F,
+  0x22, 0x28, 0x2A, 0x2E, 0x30, 0x37, 0x3B, 0x3F,
 };
 
 /*{pal:222,n:16}*/
 const char PALETTE1[16] = {
-  0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
-  0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x3F,
+  0x10, 0x03, 0x0B, 0x0F, 0x13, 0x17, 0x1B, 0x1F,
+  0x22, 0x28, 0x2A, 0x2E, 0x30, 0x37, 0x3B, 0x3F,
 };
 
 /*{w:8,h:8,bpp:1,count:2,brev:1,np:4,pofs:1,sl:4}*/
 const char PATTERNS[64] = {
-  0x00, 0x00, 0x00, 0x00,
-  0x3C, 0x3C, 0x3C, 0x3C,
-  0x56, 0x7E, 0x56, 0x56,
-  0x7E, 0x7E, 0x7E, 0x7E,
-  0x62, 0x62, 0x62, 0x62,
-  0x3C, 0x3C, 0x3C, 0x3C,
-  0x18, 0x3E, 0x18, 0x3E,
-  0x18, 0x7F, 0x00, 0x7F,
+  0x7C, 0x1C, 0x64, 0x64,
+  0xFE, 0x7E, 0xFE, 0xFE,
+  0xD6, 0x7E, 0xD6, 0xD6,
+  0xFE, 0x7E, 0xFE, 0xFE,
+  0x66, 0xE6, 0xE6, 0xE6,
+  0xBC, 0xBC, 0xBC, 0x3C,
+  0x18, 0x18, 0x3E, 0x18,
+  0x7F, 0x18, 0x67, 0x18,
 
-  0x00, 0x00, 0x00, 0x00,
-  0x00, 0x00, 0x00, 0x00,
-  0xFF, 0xFF, 0xFF, 0xFF,
-  0x55, 0x66, 0x77, 0xFF,
-  0xC0, 0xC0, 0xC0, 0xC0,
-  0x05, 0x06, 0x07, 0x08,
-  0x00, 0x00, 0x00, 0x00,
-  0xFF, 0xFF, 0xFF, 0xFF,
+  0x7D, 0x3C, 0x02, 0x3C,
+  0x7D, 0x3C, 0x9A, 0x3C,
+  0x7C, 0x3C, 0x83, 0x3C,
+  0x7E, 0x3C, 0x81, 0x3C,
+  0x3E, 0x3E, 0x00, 0x00,
+  0x36, 0x36, 0x00, 0x00,
+  0x36, 0x36, 0x00, 0x00,
+  0x00, 0x77, 0x77, 0x77,
 };
 
+// convert a mono bitmap to 4-plane
+// just copy each byte 4 times
 void expand_monobitmap(const char* src, int count) {
   while (count--) {
     char b = *src++;
@@ -59,45 +66,51 @@ void expand_monobitmap(const char* src, int count) {
   }
 }
 
+// set up mode 4 graphics
 void setup_graphics() {
   cv_set_screen_mode(CV_SCREENMODE_4);
-  cv_set_character_pattern_t(PATTERN | 0x3000);
-  cv_set_image_table(IMAGE | 0x400);
+  // set up tables
+  cv_set_character_pattern_t(PATTERN | 0x3000); // mask for mode 4
+  cv_set_image_table(IMAGE | 0x400); // mask for mode 4
   cv_set_sprite_attribute_table(SPRITES);
-  /*
-  cvu_vmemset(0, 0, 0x4000);
-  cv_set_colors(0x2, 0x5);
-  cv_set_color_table(COLOR | 0xfff);
-  cv_set_sprite_pattern_table(SPRITE_PATTERNS | 0x1800);
-  */
   cv_set_write_vram_address(PATTERN + '0'*32);
+  // convert mono bitmap font to 4-plane in VRAM
   expand_monobitmap(font_bitmap_0, (128-48)*8);
-  cvu_memtovmemcpy(PATTERN+32, PATTERNS, 32);
+  // copy sprites to pattern table VRAM
+  cvu_memtovmemcpy(PATTERN+32, PATTERNS, sizeof(PATTERNS));
+  // copy palettes to VRAM
   cvu_memtocmemcpy(0xc000, PALETTE0, 16);
   cvu_memtocmemcpy(0xc010, PALETTE1, 16);
 }
 
+// image table has two bytes per cell (name + attribute)
 void show_text() {
   cvu_vmemset(IMAGE, 0, 32*28);
-  cvu_memtovmemcpy(IMAGE, "H e l l o   P r o f e s s o r   F a l k e n ", 22*2);
-  cv_voutb(0x01);
-  cv_voutb(0x00);
+  cvu_memtovmemcpy(IMAGE, "H e l l o   W o r l d \1 ", 12*2);
 }
 
 void main() {
   char i=0;
   struct cvu_sprite4 sprite;
+  // set up mode 4 and draw initial text
   setup_graphics();
   show_text();
+  // turn on screen
   cv_set_screen_active(true);
+  // loop (once per frame)
   while (1) {
     wait_vsync();
     i++;
+    // scroll background in two directions
     cv_set_hscroll(i);
     cv_set_vscroll(i);
+    // move sprite across screen
     sprite.y = i;
     sprite.x = i;
     sprite.name = 1;
     cvu_set_sprite4(SPRITES, 0, &sprite);
+    sprite.y += 8;
+    sprite.name++;
+    cvu_set_sprite4(SPRITES, 1, &sprite);
   }
 }
diff --git a/web/images/scrnshots/apple2map.png b/web/images/scrnshots/apple2map.png
new file mode 100644
index 00000000..c7ae34aa
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diff --git a/web/images/scrnshots/astrocade.png b/web/images/scrnshots/astrocade.png
new file mode 100644
index 00000000..81f809aa
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diff --git a/web/images/scrnshots/atari2600-1-fs8.png b/web/images/scrnshots/atari2600-1-fs8.png
new file mode 100644
index 00000000..0385bd3f
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diff --git a/web/images/scrnshots/atari7800.png b/web/images/scrnshots/atari7800.png
new file mode 100644
index 00000000..f72878b0
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diff --git a/web/images/scrnshots/coleco.png b/web/images/scrnshots/coleco.png
new file mode 100644
index 00000000..6a0243a3
Binary files /dev/null and b/web/images/scrnshots/coleco.png differ
diff --git a/web/images/scrnshots/galaxian-1-fs8.png b/web/images/scrnshots/galaxian-1-fs8.png
new file mode 100644
index 00000000..c0ec3765
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diff --git a/web/images/scrnshots/msx.png b/web/images/scrnshots/msx.png
new file mode 100644
index 00000000..776623fb
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diff --git a/web/images/scrnshots/mw8080-1-fs8.png b/web/images/scrnshots/mw8080-1-fs8.png
new file mode 100644
index 00000000..e38066ae
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diff --git a/web/images/scrnshots/nes-1-fs8.png b/web/images/scrnshots/nes-1-fs8.png
new file mode 100644
index 00000000..a0ea6c63
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diff --git a/web/images/scrnshots/scope_clockdiv2.png b/web/images/scrnshots/scope_clockdiv2.png
new file mode 100644
index 00000000..6545ae2b
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diff --git a/web/images/scrnshots/sms.png b/web/images/scrnshots/sms.png
new file mode 100644
index 00000000..e86a8500
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diff --git a/web/images/scrnshots/vector-1-fs8.png b/web/images/scrnshots/vector-1-fs8.png
new file mode 100644
index 00000000..e0d9eac8
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diff --git a/web/images/scrnshots/vicdual-1-fs8.png b/web/images/scrnshots/vicdual-1-fs8.png
new file mode 100644
index 00000000..884c9021
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diff --git a/web/images/scrnshots/williams-1-fs8.png b/web/images/scrnshots/williams-1-fs8.png
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index 00000000..34057487
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