diff --git a/makefile b/makefile
index 99f53ba..b6f02e5 100644
--- a/makefile
+++ b/makefile
@@ -1,4 +1,4 @@
-SRC = src/settings.h src/fft.c src/utils_curses.c src/music_visualizer.c src/utils_mpd.c src/mt/mt19937ar.c src/beat_track.c
+SRC = src/settings.h src/fft.c src/utils_curses.c src/music_visualizer.c src/utils_mpd.c src/mt/mt19937ar.c src/beat_track.c src/invaders.c
 LOCPATH = ./bin
 INSTALLPATH = /usr/local
 CFLAGS = -O3
diff --git a/src/fft.c b/src/fft.c
index 0ea24d5..bc07bfd 100644
--- a/src/fft.c
+++ b/src/fft.c
@@ -101,6 +101,7 @@
     }
 
     unsigned int bandSize = inLen/2;
+    float winCoeff = 1; // must be multiplied
 
     for(b=0; b<inLen; b+=bandSize) {
 
@@ -108,7 +109,15 @@
         memset(inputComponents, 0, (bandSize)*sizeof(cplx));
 
         for(i=1; i<bandSize; ++i){
-            inputComponents[i] = sig[b+i];
+            // window (simple function, trapezoidal-shaped)
+            if(i<bandSize/3) {
+                winCoeff = (float)(4*i)/bandSize;
+            } else if(i>(2*bandSize)/3) {
+                winCoeff = (float)(bandSize-i)/bandSize;
+            } else {
+                winCoeff = 1;
+            }
+            inputComponents[i] = sig[b+i]*winCoeff;
         }
 
         outputComponents = _fast_ft(inputComponents, bandSize);
@@ -166,7 +175,12 @@
  * --- compute next bfreq
  */
 void
-average_signal(unsigned int *fftBuf, const int inLen, const int max, const double bf, const int oratio, unsigned int* fftAvg)
+average_signal(unsigned int *fftBuf,
+               const int inLen,
+               const int max,
+               const double bf,
+               const int oratio,
+               unsigned int* fftAvg)
 {
 	int i = 0;
     int amp = 0;
@@ -203,8 +217,6 @@
             if(j < max) fftAvg[j] = val;
         }
 
-        /* fprintf(stderr, "%d: %d, first: %d, f: %f, last: %d\n", i, fftAvg[i], first, f, last); */
-
         amp = 0;
         i += FOCUS;
 
diff --git a/src/music_visualizer.c b/src/music_visualizer.c
index 0190f7e..47f5963 100644
--- a/src/music_visualizer.c
+++ b/src/music_visualizer.c
@@ -17,6 +17,7 @@
 #include "beat_track.h"
 #include "settings.h"
 #include "mt/mt19937ar.h"
+#include "invaders.h"
 
 #ifdef STATUS_CHECK
 #include <locale.h>
@@ -33,6 +34,11 @@
 static int maxR = 0;
 static int maxC = 0;
 
+int computeStatusHeight(const int statusHDelta)
+{
+    return maxR/6-statusHDelta-2;
+}
+
 void
 process_fifo (uint16_t* buf, unsigned int* fftBuf, unsigned int* fftAvg, \
               cebuffer* energyBuffer, int nsamples, unsigned int* energyThreshold, bool* beat,
@@ -96,7 +102,7 @@
     uint32_t sampleRate = 44100;
     int nsamples = N_SAMPLES*PADDING; // adapt processing to sample rate, zero-pad
 	PATTERN pattern = LINE;
-	int statusHeight = 0;
+	int statusHDelta = 0;
 	int statusCol = 0;
 	bool toggleStatus = true;
 	bool subWindow = true;
@@ -105,6 +111,8 @@
     bool beat = false;
     double basefreq = 20;
     int oratio = ORATIO;
+    InvadersGame inv_game;
+    bool playing = false;
 
     // add it to select() set
     FD_ZERO(&set);
@@ -129,61 +137,6 @@
 #endif
 
     while(!over) {
-        switch((c = wgetch(stdscr))) {
-        case 'q':
-            over = true;
-            break;
-        case ' ':
-            pattern = (pattern + 1) % 3;
-            break;
-        case KEY_UP:
-            statusHeight += 1;
-            break;
-        case KEY_DOWN:
-            statusHeight -= 1;
-            break;
-        case KEY_LEFT:
-            statusCol -= 1;
-            break;
-        case KEY_RIGHT:
-            statusCol += 1;
-            break;
-        case 'r':
-            statusCol = 0;
-            statusHeight = 0;
-            break;
-        case 'h':
-            print_help(maxR,maxC);
-            break;
-        case 't':
-            toggleStatus = (toggleStatus == true) ? false : true;
-            break;
-        case 'b':
-            subWindow = (subWindow == true) ? false : true;
-            break;
-        case 'f':
-            if(basefreq <= 20) break;
-            if(basefreq < 250) basefreq -= 2;
-            else if(basefreq >= 150 && basefreq < 2000) basefreq -= 20;
-            else basefreq -= 200;
-            break;
-        case 'F':
-            if(basefreq >= 22100) break; 
-            if(basefreq < 250) basefreq += 2;
-            else if(basefreq >= 150 && basefreq < 2000) basefreq += 20;
-            else basefreq += 200;
-            break;
-        case 'o':
-            if(oratio <= 1) break;
-            oratio -= 1;
-            break;
-        case 'O':
-            if(oratio >= 64) break; 
-            oratio += 1;
-            break;
-        default:
-            break;
-		}
 
         // select on fifo socket
         // if > 0 means data to be read
@@ -229,7 +182,7 @@
 				print_rate_info(sampleRate, N_SAMPLES, maxC, status->song->duration_sec, basefreq, oratio);
 				cnt_over = 0;
 			}
-			print_mpd_status(status, maxC, maxR/6-statusHeight-2, statusCol);
+			print_mpd_status(status, maxC, computeStatusHeight(statusHDelta), statusCol);
 		}
 #endif
         // refresh screen
@@ -248,6 +201,70 @@
         }
 
         getmaxyx(stdscr, maxR, maxC);
+
+        switch((c = wgetch(stdscr))) {
+        case 'q':
+            over = true;
+            break;
+        case ' ':
+            pattern = (pattern + 1) % 3;
+            break;
+        case KEY_UP:
+            statusHDelta += 1;
+            break;
+        case KEY_DOWN:
+            statusHDelta -= 1;
+            break;
+        case KEY_LEFT:
+            statusCol -= 1;
+            break;
+        case KEY_RIGHT:
+            statusCol += 1;
+            break;
+        case 'r':
+            statusCol = 0;
+            statusHDelta = 0;
+            break;
+        case 'h':
+            print_help(maxR,maxC);
+            break;
+        case 't':
+            toggleStatus = (toggleStatus == true) ? false : true;
+            break;
+        case 'b':
+            subWindow = (subWindow == true) ? false : true;
+            break;
+        case 'f':
+            if(basefreq <= 20) break;
+            if(basefreq < 250) basefreq -= 2;
+            else if(basefreq >= 150 && basefreq < 2000) basefreq -= 20;
+            else basefreq -= 200;
+            break;
+        case 'F':
+            if(basefreq >= 22100) break; 
+            if(basefreq < 250) basefreq += 2;
+            else if(basefreq >= 150 && basefreq < 2000) basefreq += 20;
+            else basefreq += 200;
+            break;
+        case 'o':
+            if(oratio <= 1) break;
+            oratio -= 1;
+            break;
+        case 'O':
+            if(oratio >= 64) break; 
+            oratio += 1;
+            break;
+        case 'I':
+            inv_game = start_invaders(40, maxR, maxC); // nAliens = 40, TODO settings.h
+            if(inv_game.ready) playing = true;
+            break;
+        case 's':
+            if(playing)
+                inv_game.shoot(computeStatusHeight(statusHDelta), statusCol, inv_game);
+            break;
+        default:
+            break;
+		}
     }
 
 #ifdef STATUS_CHECK