I've seen both Laserblast and Deadly Weapon and Deadly Weapon is definitely the better of the two films.
Laserblast was just awful.
Deadly Weapon was a lot more fun because if you've ever dreamed of finding a suitcase that contains a futuristic backpack/atomic reactor with a death ray gun attached, you'll find that in this movie.
And it has Heather #1 from the movie Heathers! (the late Kim Walker)
Here's a synopsis I quoted from the IMDB:
"An expermintal gun powered by an atomic reactor is misplaced when the transport carrying it crashes into a river. The weapon soon falls into the hands of a bullied teen named Zeke, who uses it to get even with his persecutors. An army team led by the overzealous Lt. Dalton is sent to recover the weapon before it's unstable reactor overloads and causes a meltdown."