THIS GAME IS AMAZING. I ESPECIALLY LIKED THE ART STYLE. HOWEVER, THE LACK OF A TUTORIAL MADE ME VERY CONFUSED AS TO WHAT I WAS SUPPOSED TO DO OR WHAT MY OPTIONS WERE. THE "HOW TO PLAY" OPTION IN THE MENUE JUST SAYS "ABCDEFG"? THIS MADE ME ONLY DISCOVER IMPORTANT MECHANICS LIKE THE "GUN" AND "SHIELD" AFTER WANDERING AROUND FOR QUITE A WHILE.
ALSO, THE LACK OF SOUND MAKES IT FEEL A LOT LESS ENGAGING FOR ME.
OTHER THAN THAT, GREAT GAME!
EDIT: YOU CAN ALSO GO UP WALLS LIKE THEY'RE NOTHING SIMPLY BY JUMPING AND WALKING IN THE WALL.