This is really good, Uxie. Tips:
1. Make the barrel on the top (or in the middle) instead of on the bottom.
2. Even though the normal blockhead's finger does not reach the trigger, make it normal or just remove the two hands.
3. On the spawning model, when it is over the spawning brick, remove the hands.
4. Change the shells to something else than molecule parts.
That should make it spiffy.