It's simple, but for the most part, it works well. The art style and music fits the themes of the game well. It reminds me a bit of an original Gameboy game; I can also see early Macintosh like FacemeltingSolos mentioned.
I'm not a huge fan of endless runners but this one is pretty good. I do agree with ShibeyFaceGames; I think it would be better if the player was pushed along by the edge of the screen. There's also a lack of feedback when you get hit. I'm still not sure why I keep dying.
It would also be nice if the high score was persisted across page loads, and even better if there was some kind of leaderboard/high score table, but those are probably way out of scope for a jam game.
For a first game it's very good. I think I mentioned what my first game was in another comment somewhere. It was a text adventure where the goal was to feed a homeless man green slime for some reason. It was really bad in almost every conceivable way.