thanks for the constructive criticism.
regrading the shield though, i agree. the shield can be used to deflect bullets, but it does not work to well in practice.
since the ranged enemies shoot quite a lot, it's better to use the ranged weapons than the bouncing shield. the shield is better used for the non ranged flying enemies and ground enemies. i personalty find the shield quite fun to use because i like the challenge of building up enough speed to charge at the enemy and timing the hit well in order to damage the enemy, the feedback it gives adds to the fun as well.
im considering to create a remake of this game to rectify these problems.