This is actually an easy game.
1. Stay close to the station in the direction of where the enemies are.
2. Intercept and destroy as many enemies as you can. Keep on moving. Since the shield recovers fast, don’t worry about upgrading the shield.
3. When you can, upgrade the cannon 3x
4. When the enemy upgrades, shoot as many of the reds ones and keep them top priority.
5. Upgrade the ally once
6. Upgrade to tri-shot and then smart missiles
7. Upgrade allies again, max out shot, upgrade shield once.
8. Start chasing the yellows, you should be able to catch and beat them down easily. Make sure you upgrade the engine when you can as some of them run fast away from you. You’ll often cross the red core to catch the yellows on the other side.
9. After killing all the yellows, destroy the core.
10. You win. What score did you get? I managed to top 30,000 on my last run.