This game reminded me of Contra for some obvious reasons. I felt that there could have been a background story attached to this. It would have made the game more interesting. Like I did't even know what I was playing as. What is it? A dog, a pig, just a square with legs, eyes. Is it the character from doodle jump? Why are all the enemies I encounter so different from each other? One is a blob, one is a kind of ghost, one is wasp, and the boss is a turret or a machine that shoots me. To be honest, I have only played the first level so I don't know if all of this is explained further in the game. But if your first level itself doesn't make sense then the players wouldn't invest in the game. That's just my opinion.
The use of two button controls is good. Though, I didn't quite like the jump in your game. I think for any platformer game, the first thing it definitely has to perfect is the jump and it didn't feel good enough in your game. It felt like the character didn't have any weight attached to it. The shooting was also a bit clunky because of the control limitations. It was hard to shoot at the desired direction many a times. And why was it there? Just to fight the boss? Because I don't think we have to shoot the other enemies. We can just dodge and move. We don't get any reward for shooting any of them. Nor does it have much use because the small enemies are not one-shot kills like in Mario. I think this could have been a much better game if shooting mechanic was avoided and more focus was put on the jumping mechanic.
Don't take this comment as a negative one. I didn't hate your game. I just felt like you couldn't focus on what you wanted to make and ended up adding unnecessary things in it. I can understand, I really do. There is a really good game hidden in this. I would love to see it come out if you make any future updates.