It's alright. It still needs a lot of work yet. For one, the creeper should fall into the fire instead of on it. In fact, the fire should probably be lava. Also, there are no slope blocks in minecraft yet unless you count stair blocks. So, that should probably be changed somehow. IDK. Let's see, he is a creeper after all, so he should explode at some point. How about putting Steve into the game. If the creeper collides with steve, then he would explode and the level would be a fail. Also to note, the creeper should be full body and not just a head. Ice blocks could be added to make the creeper slide more. On the contrary, soul sand could slow him down. For these two things to work, friction would have to be added, which there seems to be none of. TNT blocks could be added to explode when clicked on, sending him into the air or giving him a push. Here's an idea, put the creeper into a minecart. That would allow for slopes with the minecart tracks. Also, it would still allow the creeper to go up hills until gravity got the best of him. Not to mention, creepers can actually get into minecarts. If the mine-tracks were to end, we would pretend that it would coast along until the minecart lost its momentum. If the creeper was put into a minecart, it would have to look like it too. Perhaps diamonds could be placed throughout the levels as something you could strive to collect. Obviously, sounds from the game's soundtrack would have to be added. For instance, throw in the lava sounds. If the creeper burns to death, throw in that hissing death cry he does. Perhaps add in the ambient background music that is always playing during the game. You get the idea. The cursor in-game could be a diamond pickaxe. Also, when one of the blocks are broken, the mini spinning block could fall to the ground. If that were the case, the mini block could fall onto a wooden pressure-plate and cause some redstone effect to occur, like a piston activating. If the lava thing gets boring, you could switch it up by drowning him in water. Perhaps death by cactus? Or maybe, suffocation by sand or gravel. For the background, make different scenes. Like a theme for the level could be a different biome, including the nether and the end. Well, I'm just about out of ideas. It took me a good half-hour to think of all this. I hope you like my ideas. I hope none of them offended your original ideas. If anything, I am way too damn "CREATIVE" (pun intended). Yeah, I wouldn't mind playing this game again. If you want any more ideas, just P.M. me. Good luck with the game.
P.S. This is probably the most time I've ever spent making a helpful review.