This game is awesome. Great job on this one.
Here are some things I noticed:
1. The score keeps increasing after game over. I think the spawn rate keeps going up as well.
2. The spawn rate felt a little inconsistent. Sometimes the gaps felt larger, and then they were small, but then they were larger again.
3. Maybe you could add a clear indicator of which number is HP and which is the score.
This game is so fun, though. That background scroll is also really satisfying.
Your game is looking great so far! While playing, I did notice a few things:
1. The player moves faster when moving diagonally.
2. When I was invincible, I would sometimes bounce when colliding with enemies, and sometimes I would not.
3. One time, I collided with a vehicle and flew into the air.
4. The cars are spawning on-screen. Maybe you could make it so they appear off-screen?
5. The player is safe as long as they stand next to the wall. The cars can't hit them there, so you'd have to increase the spawn range.
Besides those bugs, I would only recommend adding a score, maybe increasing the difficulty over time, and adding UI elements to the game.
