Vectors (Shooter)

No need to upgrade speed (started really lagging at level 7, at which time it stopped responding until I died; until that point I could easily outmanoeuvre the enemies, which all travel at the same speed I do). Also, all enemies seem to have the same behaviour, making avoiding them and drawing them into my line of fire even easier. Some enemies should be faster and weaker, some slower and stronger. Ideally, some would shy away from the direction player is aiming or try to get in front of the direction the player is traveling. Variety with enemies is easier if you're going to have them fire, though that is not strictly necessary to make a good game. There is no reason NOT to fire, so you shouldn't make the player hold the mouse button down; either have auto-fire or use ammunition or at the least have a bonus of some kind for accuracy. Try to add something that sets it apart from other games in the same genre. Good start, though.

Our character needs to be mode in the center of the screen, for example if I move to the left at max, after, if I move right, I won't ennemies coming from right !

Quite nice, if generic, shooter. A few things i'd like to see: 1. autofire - 2. keeping the ship in the center of the screen. - 3. Lag starts to really be an issue at level 8, which is a shame since that's the first level that has challenging enemies (fast swarmers). 4. if you can think of something nice, add a twist / unique touch to distinguish it from similiar games: be it an unusual mechanic, crazy enemy attack Patterns/ strategies, etc

It needs some sounds when you shoot and "kill" ennemies, I think it will be more immersive.

Game seems a bit slow, and you need balancing on the upgrades. The enemies have too little variety and randomness. It's not sheer number or firepower that kills players. It's variation of attacks that force players to focus, or die trying.