Playability Improvements

[Stefan4472]

• [ ] The game should start a bit faster.
• [ ] Alien bullets should collide with obstacles. Otherwise, it feels unfair.
• [ ] Limit the maximum number of aliens that can be in the game at a single time. Set the limit to 3 or 4.
• [ ] Smoother controls -- maybe something that takes control input as a "force" and has a bit of inertia. The idea would be to make it feel more like you're controlling an actual ship.
• [ ] Only start map generation once the player has hit the "started" position.