I'll keep this brief: I played some Boltgun 2 and I'm still buzzing about it. It's extremely similar to the first Warhammer 40,000: Boltgun, but more and different. It could be a perfect sequel.
I already consider the original Boltgun a nearly perfect throwback FPS (or boomer shooter if you prefer) for the way it walks a fine line between modern convenience and '90s sensibilities, so developer Auroch Digital is starting from a great place. Boltgun 2 is more escalation than reinvention: more weapons, more biomes, and double the protagonists.