The only time I ever had ammo issues was at the beginning; by the middle, I have too
much ammo and not enough space, and too many health items.
I can't emphasize Mustrum Ridcully's Points 1-3 hard enough. Waves of monsters are great - even back to back encounters, or a normal encounter where the elite doesn't show up until round 5. During their first extended rest, and perhaps their sixth, they should be interrupted. Something coming through the vents (so to speak). The haven they used for rest last time suddenly is no longer useful.
My own suggestions:
0) Make sure your players are interested in this kind of game.
1) Hit them where it hurts: their resources. Monsters that eat healing surges. Monsters that temporarily disable dailies/encounters (or possibly eat a leader's Twice-per-encounter healing power). Do this SPARINGLY (messing with powers is cheap). Do this to make a normal fight suddenly tense.
2)
http://www.enworld.org/forum/general-rpg-discussion/241614-creative-combat-objectives-other-than-kill-em-all.html]Objective Based Encounters[/url]; they don't need to just kill the enemy, they need to protect an ally who's Opening a Door. The air is rapidly being sucked out of the room and they need to stop it. Etc etc. This creates
tension because the monsters aren't the real threat, they're just obstacles.Consider skill challenges mixed with combat, too.
There's also nothing wrong with creating an encounter where "You can't hurt this monster until you do X, or you can't really hurt it" as long as you MAKE THAT OBVIOUS TO THEM; if a player spends a daily and it is all for naught, you will get angry players. Also make sure the design is Good.
And as far as "Video Game Boss" fights,
http://feedproxy.google.com/~r/omnivangelist/FvNp/~3/-SJ5dcAa48Q/]here's[/url]some
http://www.encounteraday.com/2009/04/27/multi-part-bosses/]suggestions[/url]
3) Vicious encounter design. Artillery monsters on platforms PCs can't reach via melee, and the PCs have to run past the platforms to get where they need to go. Do they stay and shoot, making themselves targets, or chance a few hits and make it to the end? Does your party lack a role? Occasionally use a large dose of monsters that missing role would work well against (missing a controller? Buckets of minions and several swarms). One PC gets separated/locked in a room with a few minor enemies (minions mostly); the PCs must now rush to find a new way in to save their ally, while being chased by enemies.
4) Make it plain to your players that unless they are locked in a room or facing a "Boss"/monster wave battle, they can run away (such as running from swarms). This handles the "Die, come back to previous save point, and you know the monster's locations" circumstance. Sometimes the players DO need to step back and regroup; part of the goal of overcoming what's ahead takes strategy, because you are being particularly nasty.
5) Give them the occasional NPC to
talk to. Unlike survival horror games, the players might get bored if it's constant fight fight fight. Give them a survivor they need to protect, or someone with info, or maybe even an intelligent monster who's in as deep as they are. Hell, this NPC might even be an ally (who dies right after they have been useful).
6) Give a breather. You need to let the tension ease sometimes, so they don't get used to the tension, and when it spikes, it makes a difference. There are certain points in the game, for instance, where there you've killed everything in the area and you can walk around safely.
7) I agree with using new enemies, instead of monsters they've faced elsewhere (although, the occasional out-of-place D&D monster, who's equally as scared as they are, can be a nice change of pace). But using Dead Space as an example, some of the monsters you face early on are brought back, but tougher. Either just higher levels (and with nastier appearances), or spice it up by giving them upgraded powers (that thing's ranged attack becomes an area burst, the nasty melee attack becomes a close burst 1, etc).
8) Don't ignore set pieces. A giant boulder that the party can push in front of a door, slowing down the wave of enemies? They'll eat that up, if you can give enough hints to let them do it. Or, a giant set piece that functions as a weapon against a very powerful enemy? Delicious.
9) Be aware that PCs can really throw status effects on a monster fast. Stacking Stunned, Dazed, etc, will really mess up your nasty solo's day fast. So, consider some house rules to address this, or just cope with it.
10) If you want to have the PCs stuck in this situation for a long time, give them an option that allows them to upgrade their equipment. A natural (but limited) source of Residuum, or just raw residuum in containers, that teh PCs can use to either make their own items or upgrade their own stuff. This not only simulates the PCs buying things, but it also covers the issue of loot (we have tons of gold... great, no shop to use it in).