Its pretty broken if you hold down space you'll shoot an infinite barrage of bullets

i win the game an a score of 500 points

It's a rehash of a classic game. Nothing new or exciting but it works and functions. Basic controls at the beginning would be good.

It's a playable space invaders game, nothing terrible, nothing great.
The problem is that there's not a lot of going on – it's just ‘shoot everything’. Even the original Space Invaders had more content: barricades, different kinds of enemies, increasing speed and UFOs for bonus points:
https://youtu.be/UZlEXl9xgR8
Because your game plays out more or less the same every time, it will get boring after two or three rounds.

Interestingly enough, even a victory results in a Game Over screen with 500 points – another reason why the game doesn't have much replay value. There's no ‘beating your high score’, just ‘get 500 points again’. You should probably restart the game but keep the accumulated points to see how far can people go without dying.
A restart button on the ending screen would be welcome, too.

Also, whenever you shoot, the enemies do as well – I don't know if it's supposed to be a feature or if it's a bug. The player is surprisingly fast and the shots have no cooldown, so the best tactic I found is to constantly move left and right and keep shooting in order to avoid enemy attacks which probably isn't what you intended.

Overall, it's an okay game, just not interesting enough.