New enemy variety, new ammo types and a new weapon, cool new vehicle (and the game has a vehicle now), new maps and map design (a lot more scrambling around ruined structures this time). It's great, all of it. There's even a new version of the main campaign that adds in all the new expansion content into the base campaign's levels, with occassional tweaks to the level design itself.
It's all the best parts of the Build engine holy trinity: Duke's attitude and realistic environments, Shadow Warrior's enemy variety and generally better weapon balance, Blood's movement and map variety. And with the 3.0 update for Aftershock, it's also cleaned up a lot of those game engine's jank that it inherited from the original Build, which is perhaps the most impressive technical achievement of the game. It almost feels like sacrilege, I mean without the jank is it even a Build engine game? Of that first trio of retro shooters from 2019 - Ion Fury, Amid Evil, and Dusk - this is absolutely my favorite. It does such a fantastic job of balancing "plan your fights to make them easy" and "scramble through the fight or you'll die", and every weapon feels like it fulfills an important role in your arsenal. The electrifryer easily counters head spiders, and the crossbow secondary can be supercharged to wreck giant mechs, the penetrator with short bursts to the head quickly downs missile torsos. Secret hunting was vastly improved in the 2.0 update when the radar became capable of highlighting secrets as well as enemies, and the secrets are consistently worth tracking down on Hell Hath No Fury. Which is great, because exploring the interesting bits and bobs scattered around the corners of a Build engine map is half the fun. It's just a really good sprite-based FPS with long, beefy campaign. And the Aftershock expansion is great too, get that.
