When it comes to mods for old games, I love seeing just how far their structure can be pushed with modern engines, but there's still some wisdom in the old ways. Viking-themed Doom mod Rekkr takes it all the way to the old school and back again, uphill both ways in freezing snow.
Built to authentic retro specs (making it compatible with even the original DOS version, should you so wish), there's no vertical aim, crouching or jumping here, just 25+ levels of weird techno-magical viking violence, with new enemies, weapons and art.
Playing Rekkr is a strange and nostalgic experience - heck, even the mod's website feels like it's from an era quickly fading from the internet's memory. While I've been running it through the GZDoom engine for slightly nicer graphics, widescreen and higher framerates, this should be playable on a 486 - maybe less, if you don't mind a postage-stamp sized game window. It looks, sounds and plays like a long-lost Doom derivative; maybe some strange, unlicensed spinoff. A pitch that never quite made it, like Hacx, but actually finished and playable start to finish.
Rekkr is a clear labour of love, and a real effort has been made to capture that grungy, rough '90s feel, even if there is a new and slightly weird pseudo-Nordic Steampunk-ish spin on it all. It's primarily the work of modder Revae, but with guest maps from a bunch of the best and brightest in the scene. It's even fully playable in multiplayer, and many maps have special arena zones dedicated to deathmatch, which is a step up over the original game.
To play Rekkr, you'll need the mod itself here, the original Doom (available on Steam and GOG) and while you could play it entirely old-school on a retro PC or emulated via DOSbox, I'd recommend just going with the GZDoom engine for ease and readability. 320 x 200 VGA graphics are a little rough on the old eyeballs these days.