This is really fun. I'd love a second level.  The chutes in the screenshot look great.

In the original arcade version, you accelerate the ball by adding to the particular velocity.  This would result in infinite speed (like Asteroids) but you also apply friction by multiplying by a number close to 1, like 0.95 or whatever.  If there's no speed, it doesn't do anything, but the greater the speed, the more lost to friction.  When that amount equals the acceleration, you've reached a top speed, or limit.

In your version, there's accelerated movement with no friction and a top speed applied.  It's very close to the same thing, but it's not quite the same thing.  In particular, the old approach allows for a less steep curve of acceleration and a steeper curve of deceleration - when you accelerate, friction works against you and when you stop, it works with you.  This is, in my opinion, a pretty important part of the controls in this game.  I hope that's useful.