I don't understand why bombs should be any different than rocks, if anything, bombs are lighter than rocks
And I have said this many times before, yam, alien etc. randomness is ok in my book, since you can learn to control these things to reduce the luck factor. Rock/bomb pushing you can do nothing about, you don't learn to push the rocks better, so having a lucky push actually doesn't make you feel successful/rewarded, it's just luck. However, when you control a lot of yams by a better method than you had earlier, now that's the great and rewarding thing about this game. Of course there are levels where yams etc. are pure luck, but I don't mind that at all, they are just a different breed of levels. Yams, aliens are living things, thus there randomness is natural and makes them feel more alive. Rocks/bombs should always move the same way. They always move the same vertically and they should always move the same horizontally.