Half-Life 2 mod Evacuation lets you pit antlions vs Combine in the woods
Become a Combine harvester
If you go down to the woods today, you're in for a big surprise. Spoilers: the surprise is an ambush from Combine soldiers and antlions, sent to welcome you after your helicopter crashes in Half-Life 2 mod Evacuation. There are zombies, too. Maybe today was not the best day to go down to the woods.
You get an axe rather than a crowbar, which is appropriate. I like the idea of wandering among those trees, then lurking back to watch the antlions turn on the Combine. That can happen, according to the mod's Steam page.
It's billed as "story-driven", with voice acting, puzzles, and an original soundtrack. One of the Steam reviews estimates it'll take you around one and a half to two hours, and there are mixed reports about the quality of the voice acting. That's fine. Ropey acting can be part of the fun with mods.
If you're after more, Entropy: Zero 2 is another custom Half-Life 2 campaign that recently recently won ModDB's Mod of The Year awards. You can download that one straight from Steam, too.
If that still doesn't slake your thirst for Combine blood, you can check out Dominic Tarason's round up of the best Half-Life 2 mods. It's from a few years back, but Combine blood stays fresh for decades.
You will need Half-Life 2 to play any of the above. In the unlikely event you don't own it already, it's £8.50/$10/€10 on Steam.