Great Game, thanks for giving it some love!
Few things i noticed that are different:
Minor things
The "secret wall" in lvl1 does not make the sound
Barrels have lower Area of Effect, making them useless at the few points where it mattered.
Bigger things
Weapon 6 has no splash damage, which was the unique point of it (also very important for later guns).
Not being able to change the direction of shooting on automatic guns during fire its actually annoying at many points.
Hope to see the full version soon <3