I'm running out of ammo after a very short time, manage to take down one enemy at best.
And I second the problem about bullets being invisible on some backgrounds.
It has a few nice features like the bomb placement and the slo-mo death, but it's quite barebones in other important areas. Like the enemy behaviours, who leave little room for error. Some windows of opportunity in their behaviour to place an ideal attack or some repositioning to readjust one's aim would create a more varied combat experience.
The bombing didnt seem to have much tactical depth, perhaps it could have more range and hurt enemies. or perhaps just stun them.
Good start, flesh this out a bit, gonna be good!