As soon as I saw your app's cover image, I immediately knew that tileset pack - I actually used the same for one of our earlier projects. It's a great pack and it looks really good with your game. It's a great game concept - it made me wish there was a win condition of some kind. Maybe if you expanded it you could set level conditions of outlasting a certain amount of time or changing it up a bit to collect a certain amount of hearts within a set time period. I did notice I only saw one of the saw blades once in the three times I played the game; more saws might add a little more challenge. I liked the animations and stuff as well. Nice job!