Crestfallen is a very short single map for Doom II by Swedish Doomer Martin Friberg aka "[cocoon]". There's no story, just a warning to players to use their fists to make sure there is enough ammo to finish the map. CRESTFAL is clearly influenced by Malcolm Sailor's CHORD series, so much that Friberg mentions it in the .TXT. You will be pitted in a series of small survival challenges in cramped areas, emphasizing close-quarters combat and your ability to dodge. It's certainly not as large as the CHORD maps that inspired it, or as difficult, but Friberg manages to nail the desperate scavenger-style gameplay.
For starters, he immediately puts you on your toes by facing a horde of imps toward you. A handy berserk pack is close by, so you're not in any real danger, but it's the initial impression that's important. Once you dispatch the impish threat, you have three choices to make. Each switch opens a new challenge and dumps some monsters into the hub. The challenges feature a few monsters, give a new weapon / ammo, and require some fast reactions. When you conquer the gauntlet, you release the final surprise, and you will want to make sure you're adequately armed, or the situation could quickly get out of hand.
Friberg hits all the right notes in encounters and layout. The economy of design regarding the teleporter traps is clever and each challenge arena is tailored to its specific purpose. The height variation in the plasma rifle room is very distracting, making the otherwise simple monsters a credible threat. I'm not exactly sold on him warping more imps into the starting area, but I suppose it's a decent way of neutering the final fight by reducing the statistical probability of you being overwhelmed by tougher, high-HP enemies.
Though it's very short, much care has been poured into the detailing of this map. Check out the metal struts or the few instances of lighting. I particularly like the way the sagging skin graphic is used in the main area's ceiling, making it appear as though the light level fades as you get lower to the ground. It all ties together for a small, potent package. If you're in the mood for a short, CHORD-style map that doesn't bite back too hard, you should play Crestfallen. Those who dislike scavenger gameplay should avoid, though if you've never tried it and want to dip your toes in the water, this WAD could serve as a nice introduction.