Wow, this is progressing really fast. The new weapons and companion look awesome, can't wait for the next build!
Programming weapons is a very easy process on Infected Slaughter, and before ammo limits and weapon switching was added, in Soviet Undead as well.
You basically create a new Global.shoot variable to store the weapon, Go to Alarm to set if a weapon should be able to fire again or should reload, set it so that in animation end once reloading or firing is over you revert to default, and copy and paste a code block from Glob Left button to handle firing.
Things get more complicated when you want to make details, such as more sprites, shooting from a gun's tip rather than the center, adding multiple held weapons, et. al.
Also, I was hoping for a source, not an exe