While the starting idea is interesting since I do like a lot games revolving around getting bigger and bigger, this game does not succeed in taking the cake.
-First lets talk about the overall look of the game. This game looks like it was made ten years ago, if so he would look acceptable but it is not by today standard. The sprite used for the pig is too basic and the hud is just a couple of letters incrusted quickly atop the screen. The platforms are just big lines, there is little to no background and you can actually see the line where the background is repeated. This is unnaceptable by quality standards. The breakable blocks doesnt look like breakable blocks. It does look like the game was made in mspaint. First impression is paramount, a game that look that bland and rushed will aggravate it's ranking. Even though looks arent everything I think it is one of the main issue with the game. If you gave it a little polish by making a more complex character sprite or some detail backgrounds it could help a lot. Maybe your specialty isnt drawing but coding. In that case I would suggest you find an artist that would take over the whole drawing part.
-Now let's go to the sound, the retro music is okay but I feel it somehow doesnt quite fit with the style of your game. Perhaps because it doesnt seem that your game is retro. The noise the pig is making each time he eat an apple is fine at first but it's really getting on my nerve after the first dozen apples. You should look for a more satisfying sound that would give that extra push the player is looking for while getting the apples.
-As for controls the pig feels heavy to control especially when he jumps, but not in a good way. you should start to feel the weight of your character as he increase in size, not when he's small, besides there are no difference between the small pig and big pig control except for the fact you dont really fit through some spaces anymore. The pig look more like a cardboard cutout than an actual pig. Maybe you should try to make it feel like some kind of softball, so even if he gets big you can try to wedge him through slightly tinier spots instead of having him go into a complete halt everytime the obstacle is an inch over his height. There are also little possibilites is gameplay. It would be nice to know when you are heavy enough to smash trough some blocks (And that those blocks are breakable in the first place. Plus adding some extra move would smooth out the control and give the player the idea he has more control (Possibility to double jump or pile dive up or down or maybe spin to give yourself some momentum ala sonic)
-On to level design : This is a cluster, a complete mess. There is barely anything to salvage here, the apples seems to have been put at some place at complete random, the platforming makes little to no sense, There are barely no indications on what everything does. On my first try I ended up reaching the pool of mud without even knowing it would end the level by going underground and then going up the only way I could by the blue ladder. It also seem that you cant just collect apple randomly since some apples are quickly getting out of grasp if you go too big so you have to carefully pick what apple you want first. This gives to the game a layer of exploration and think through that shouldnt be the focus, not if you cant see all of the map at once.
-Gameplay wise there is one level. the goal is to have a 3 stars ranking. But with the previous flaw I mentioned I doubt anyone would have the patience to go through the game to achieve that score.
The game should provide more levels, with puzzles to make itself interesting but could also be a relaxing destruction game. It's up to you now. But most importantly : Put actual effort into the design.