3. The Crowbar
A staple of the Half-Life franchise is Gordon Freeman's trusty crowbar, and even if he doesn't appear in the film, this weapon, almost a character in of itself, definitely needs to. At the start of the majority of the Half-Life games, you're weapon-less, and the first thing you come across is a crowbar; it might be a cliche by now but it's something we love seeing make an appearance time and time again. The start of the film needs to follow suit, building up to us using a crowbar to bat away the pesky headcrabs. It's arguably the most iconic item in the entirety of the Half-Life saga, so it needs to...crowbar...its way in there, and an in-joke or two about it probably wouldn't go amiss either.