Duke nukem 3D is kinda the most adult shooter ever if you compute the ratio of age/controversy/sex/blood/possibilities.

It's a sort of duke roguelike with 100's of potential levels, you play through a a certain random number of them in a run. Also you unlock all sorts of power ups as you progress, enemies also get stronger and get random buffs. + Theyve added a load of mechanics, more weapons, enemies, more playable characters etc.

Even the enemy AI could be modified (albeit relatively limited) by editing the text CON files.

Anyone else remember playing over LAN with friends, dropping a Duke hologram in an elevator along with a bunch of pipe bombs hidden at its feet?

Play the (only?) WASM demo at https://midzer.de/wasm/duke3d/ (ported from https://github.com/GPSnoopy/BelgianChocolateDuke3D). Miserably only software rendering right now.

I'd wish there could be an improvement of some of the old games. Not to change their character per se, but to make some small modest improvements to e. g. gameplay, usability, perhaps even the graphics - without killing the old flair it had. Anyone remember Alone in the Dark? I liked the polygons, even though nobody would use these today. So that can probably not be improved a lot without ruining the old feeling. But content-wise? Where is AI when you need it? Can't AI autogenerate more content for those games AND also improve them modestly?