I think this is a very nice game. Only a couple notes:
Bombs generally count down instead of up. So 3...2...1..0... boom would be better
I felt the gravity was too strong, As soon as you stop touching thruster, you begin to fall down very fast. I think a smoother effect on gravity would be better. Currently to fly straight right, player has to tap thrusters in quick succession.
And finally, while going left and right, it would be nice if the capsule tilted to sides slightly, I understand lateral thrusters do the job, but still a little bit of sway could make it feel more realistic instead of stiff.
I loved the graphics, level design, concept, everything!