very good job for you first game, the art is good (especially the player character looks cool), and the parallax bg is really cool. for improvments i suggest you work more on the character jumping physics (there are great videos on youtube on how popular platformer games achieved very nice jumping physics), also it is very difficult to know where is the next platform, soo half the time i'm just guessing and hoping to land on something and to not get accidently killed by the enemies.
i found a funny bug that makes the player fall indefinitely into the abyss without respawning, if you jump over the door to the left side of the first spawn, the character don't collide with the invisible wall that trigger the respawn soo you just keep falling and falling hhhh
but overall for a first game this is awesome, the gameplay is fun even if it's a bit hard and the pixel art looks realy nice.
Good Job !!