Heavy Barrel © 1990 Data East USA, Inc.
North American release. Game developed in Japan. See the original Famicom version for more information: Heavy Barrel [Model DFC-XH]
Description from the back cover:
The impossible and unthinkable has happened. Terrorists have seized the underground control complex of a nuclear missile site. It's up to you to infiltrate the installation and eliminate the leader of the terrorist army.
It won't be easy. Powerful tanks, treacherous waterways and the bridges are all part of enemy territory now. The only weapon you'll be able to defeat the terrorists with is HEAVY BARRELL - but it's been dismantled and is in pieces inside the installation itself. Once you've battled your way inside, you must find the keys and reassemble the weapon. Brute force alone won't defeat the terrorists. This isn't a job for just anyone. That's why you are here!
Click to enlarge