I'm going to end up repeating others with my critique, but I want to be thorough:
- The spikes at the bottom should kill you immediately. Once you are down there, there is no way to recover, so it not being an immediate loss is just a wasting time.
- There should be a second or two in between the player dying and the level restarting ( a space for a death animation mayhaps ). When the restart is immediate, the player doesn't have time to register that they've lost. Because of this, a lot of the time I will still be holding a direction key. So when the level restarts, my character will immediately be travelling full speed off the platform, before I have time to react.
- The volume slider on the menu doesn't change the volume in the actual game.
- The physics are a bit janky. I'm not familiar with Unity so I'm unaware of whatever method is best for making a platformer in it. I read your code and saw that you are using a rigid body, I wouldn't recommend doing this.
- I don't think this game really needs a life bar, I feel it would be better as just a one hit kill thing. All of the levels the hazards can just be ignored since you have enough hit points the just damage boost trough everything.
- That being said because of the janky collisions, it can be hard to avoid dangers at times. On the third level, it feels pretty bad to get hit by the spikes on the right edge of the platform. This would be more frustrating if it was an instant loss.
- This one is a nitpick, but I'm mentioning it because its a personal pet peeve of mine that I see from even very experienced devs: The "exit" button on the main menu only makes sense for the desktop build of the game. In a web game, this always just crashes the game and forces you to reload the page. I'm not sure how its done in Unity, but there should be some method of being able to check if you are on web or not.
- Lastly, as Yerghaiz said, the UI scaling is funky. You can't see the first life bar properly or the coin meter unless you fullscreen the game.
Sorry if my critique is too much, please don't feel disparaged. You should still be proud of the fact that you have successfully made a game for a jam, that already makes you more accomplished than a lot of devs out there. Keep at it, and your games will only get better and better !!