diff --git a/src/game_logic.c b/src/game_logic.c
index 0a2faf0..759011b 100644
--- a/src/game_logic.c
+++ b/src/game_logic.c
@@ -21,9 +21,7 @@ uint8_t *get_front_grid(void) {
 	return front_grid;
 }
 
-uint8_t *step_game(step_direction dir) {
-	// TODO: Update the grid state calculating the new state in the back grid
-	
+uint8_t *step_game(step_direction dir) {	
 	uint8_t start_offset;
 	int8_t column_step;
 	int8_t row_step;
@@ -37,7 +35,7 @@ uint8_t *step_game(step_direction dir) {
 	
 	switch(dir) {
 		case UP:
-			start_offset = GRID_SIDE;
+			start_offset = GRID_SIDE - 1;
 			column_step = GRID_SIDE;
 			row_step = -1;
 			break;