I've only played the demo on Steam, but the more I see of this old prototype, the higher my hopes get for the future of this game, because you guys seem to really understand what works and what not.
There's lots of things in the removed levels that really seem to kill the flow. Some too complex levels that turn into puzzles to figure out an efficient route, some have too many enemies in a room that force you to play too defensively, some drop in enemies at a too slow rate, making you pace around a room for too long...
The Steam demo however cuts out all the drag and delivers only the finest turbo-violence racetracks. Every level flowing so perfectly buttery smooth, allowing you to push forward near constantly like the unstoppable object you are meant to be and whenever there would be too many enemies in a room, there's always some explosive or an Uzi user strategically placed to still enable that aggressive push.
It tells me that we are on the same page about when this game is at its best: when you play fast and furious and absolutely will not stop... ever, until they're all dead!
And man, do you make guns feel good. That shotgun feels AMAZING even though it's the least efficient of the bunch and the bang of the pistol is just right. (though the Uzi's sound could use a little more punch, like the other two have).
I also really appreciate the quirky style and goofy humour. There's just too few games that ditch realistic graphics/settings and just let creativity go wild like this. I wish more games would give the rule of cool more power.