diff --git a/src/index.html b/src/index.html
index ba83197..42c7a74 100644
--- a/src/index.html
+++ b/src/index.html
@@ -13,8 +13,9 @@
     </script>
 		<style>
       *, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
-			body, html { background-color: #111; display: flex; height: 100vh; width: 100vw; justify-content: center; align-items: center; flex-direction: column; font-family: sans-serif; }
-      canvas { margin-bottom: 1em; }
+			body, html { background-color: #111; display: flex; min-height: 100vh; max-width: 100vw; justify-content: center; align-items: center; flex-direction: column; font-family: sans-serif; }
+      canvas { margin-bottom: 1em; max-height: 100vh; max-width: 100vw; }
+      a { color: #fff; margin-bottom: 1em; }
 		</style>
   </body>
 </html>
diff --git a/src/main.rs b/src/main.rs
index 6bd870a..de0d543 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -4,6 +4,7 @@
 use bracket_lib::prelude::*;
 use std::collections::VecDeque;
 
+const VERSION: &str = "0.3.0";
 const SCREEN_WIDTH: u16 = 80;
 const SCREEN_HEIGHT: u16 = 50;
 const FRAME_DURATION: f32 = 35.0;
@@ -21,12 +22,10 @@ struct Obstacle {
 impl Obstacle {
     fn new(x: i32, score: u32) -> Self {
         let mut random = RandomNumberGenerator::new();
-        // TODO: make smaller with score
         Obstacle {
             x,
             gap_y: random.range(10, 40),
-            // TODO: increase difficulty
-            gap_height: u16::max(2, 15),
+            gap_height: u16::max(5, 20 - (score as u16 / 3)),
         }
     }