Great job submitting a game! I did two playthroughs, one only upgrading thrusters and the other upgrading shields. I think I favored the movement more. Shield seemed a little trickier, especially trying to stay in one spot. I like how one relies on timing and the other movement skill. Visually it was sometimes hard to determine if I was going to get hit or not until it was too late. Maybe making lanes or having a grid overlay would help? As for difficulty it took me three runs to beat the game. Those double laser blasts hit hard when I didn't have enough shield meter left. But, after I got used to the gameplay it was pretty easy to win.
I think the main thing missing here is a little more variety in gameplay but for a game made in a week I think you made a smart choice limiting your scope and keeping it minimal! I had fun regardless so great work. Thanks for coming back for your second Nokia Jam! Hope to see you next year!