In concept, I can see this as being useable with real steel. Having a .45 platform that can be shouldered would help with accuracy and managing the recoil from that big round. But as was mentioned, this would be more of a range toy that a practical service weapon, even in the PDW role. The lack of select fire and the low ammo capacity would put this gun at a real disadvantage in the hands of those that would need to use it. Even if extended mags were made available, they would be of fairly low capacity because of the single stack design. Any mag of more than 20-ish rounds would be long and unweildy and quite heavy.
In airsoft, there's no reason this couldn't be used, although it would still put the user at a disadvantage against AEGs. In a pistol / shotgun only game, this would probably work well. I can't see this design being useful in any other role though.
As for looks. Well.... EEEEEEWWWWW.... As AP said, it looks like a paintball pistol.
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