A to-the-point, very fun game. Incredibly pretty, I'm a sucker for retro. The simplicity was appreciable, with the timer being completely visible in a large font behind. It let me zone out and play the game idly as I paid attention to it, and that's a commendable user experience to emulate.
Things I think may need improvement: The difficulty curve - it ramped very stably in the beginning, started peaking around minute 4, then had a bit of much-appreciated rest-time, but sadly never went up again. I stuck around till 8 minutes but I'm guessing it doesn't increase. Also, the game could support a lot of cool features in its current state -powerups, enemy types and so on to.
Solid entry, I'd be proud to make this. Cheers!