Here are more candidates:
P.S. All of the Lotus (TEC) Games have hidden games with shooting in it.
(
I II III)
Joe Blade II. (The 1st one has guns)
HeroQuest
Hmm,
Fire And Ice - Shooting/Throwing bubbles (icewhateverthingies) ?
Titus the Fox
Hoi
The Flintstones,
Garfield BFHD,
Garfield Winter Tail,
Dithell's Wonderland.
PP Hammer maybe.
...