Since I saw a few of your comments on other games, I thought I'd give it a try :D

Gameplay

It was fun at first, dodging the lasers and trying not to get locked on. I liked how easily you made the difficulty increase by just adding another ship.
Then I realised that if I kept going fast in one direction, the ships couldn't hit me, even with the velocity cap. To solve this, maybe make the ships shoot beams (raycast) rather than lasers (projectiles).
Also, the lock on never left the asteroid after I started going fast. 

Visuals

Maybe giving each enemy a different colour for their ships and lock-on symbol would make them more interesting.
Not really much else to say as there wasn't much. But since this is a quick jam, the visuals were pretty good.

Audio

The music track was too short and didn't loop perfectly so it got a little annoying after a while.
Also, there should be some sound effects when a ship has locked on or a new ship has arrived or when lasers are being fired.

Enjoyment

It was fairly fun. Felt a bit slow to start with and nearly impossible at the end (if you play it properly).
Just wish there was something more when you finally hit Earth. Maybe an explosion?

Themes

Rock is hard, lasers are fast. Kinda fits, not super strongly, but strong enough :)

3 Hours

I wonder what you could have done with that 2.15 seconds remaining :D Very nice time keeping and well done for getting it done so close to the deadline!

Hopefully my comment doesn't sound too harsh; just trying to give some constructive criticism :) It was still a great game jam game!

I finished by exploiting velocity I think .. I gained so much acceleration the ships weren't able to hit me even once by just going left and left and left ...

Super interesting take on an old classic! Impressive work for around 3 hours.

The music didn't loop properly which was "mildly annoying" but it did have music and this somehow added some sense of "impending doom".

It took me a sec. to get the hang of it.  Very cool.  Mechanics were solid.