My 2 cents: I think it's more important to differentiate between floors than between rooms. I don't have a problem with the randomness on any specific floor. In some ways, it's better to not have rooms that are too distinct, because then the player picks up on the pattern. But it's disappointing to finish a level and arrive at another, very similar level.
In Isaac and Nuclear Throne, the enemies are very distinct and they change throughout the levels. The ship enemies aren't really that distinct, and so, the level change isn't so obvious -- at least from my limited experience.
- Could we have some levels where you don't have to beat a boss, but instead waves of enemies? Bosses are the most repetitive element of this kind of game (same thing in Isaac and Nuclear Throne).
- Levels definitely need to have a distinct artistic style.
- Random Modifiers: per-floor, and per-room. Random modifiers could make enemies/you faster, stronger, weaker, fiery etc.
The art, honestly, will probably be the thing that really determines this one. As a rule, games in this genre have little difference between floors as far as the actual gameplay goes, and frankly, this is likely to end up very similarly.
Enemy "waves" I'd be against because A: only certain enemies would be applicable due to movement patterns (only a couple of very specific types would work here), and B: the game isnt really designed for it, and neither are the enemies. Only the absolute weakest foes are viable for "waves", and even then, not necessarily. The idea of things like enemy groups/swarms (and I dont just mean the little groups that the funky "swarm" enemy type does, considering how they work) were an idea that originally I'd wanted to do in this, like, you know, large numbers of "popcorn" enemies in a room like you'd see in a shmup, but Chris had pointed out a large variety of reasons against it, all of which were good, and the idea was immediately scrapped.
Further into development now and seeing where things are going, I'm absolutely certain he was right about that one.
There's also the simple fact that, in games with shmup elements, everyone expects a boss. I can see people deciding that "waves" instead of a big metal monster are "lazy" somehow, because people tend to think that way, much to my nonstop annoyance. Not to mention players thinking something like "why is it just more enemies? I JUST fought a ton of these guys all over the floor".
Though, this is part of what some of the special rooms are meant to do, such as that whole idea of the survival room where all you do is dodge a ton of crap for a certain amount of time.
Random modifiers wouldnt really work here either, at least not for enemies/bosses. For many of them, the moment a stat changes, is the moment their attacks become distorted and possibly undodgable. This wont be as apparent right NOW as it will be later when some of them receive hard-mode upgrades. That one's a big no-no. As for stuff that affects the player, hmm.... I dunno. It'd have to be something that wouldnt do anything to the player's controls; in a game like this, THAT would do nothing but enrage the sorts of players that are likely to be attracted to this. Hell, it'd do the same in other games too (cant think of any that do this, actually). This whole concept of modifiers usually isnt seen in action-roguelikes but only in turn-based, for the most part. It ends up being too difficult to get right. Hell, Isaac, one of the best ones there is, does it, and it does it COMPLETELY WRONG. None of the modifiers actually add a single thing to the experience, and every single one of them is *just* annoying. Not challenging or requiring you to think, no, *just* annoying. If even that game cant get it right (or come anywhere remotely near) it's just proof that it isnt going to fit this genre.
The one thing that I *know* will change, at least, is the simple fact that right now, every enemy (well, most of them) appears on any floor. By the time the game launches, every enemy will be set to certain floors or certain ranges. This goes for the bosses too, most of them are just set to appear wherever, certain specific ones are set to floor 4 or higher.
As for the enemies being distinct visually.... that one, there's nothing really to do anything about. Outside of the actual attack patterns, that's all about the art, and that's stuff that there definitely isnt time for (because a huge amount of it is about animation and stuff). And dont forget, even Isaac re-uses the funky hell out of art assets, when it comes to enemies. Even the big expansion to Rebirth didn't actually add that many GENUINELY new enemies to the game; what it mostly did was add typical "palette swaps", enemies that were altered to look just a little different, instead of being totally new creations (and have slightly differing or added to patterns). Such as Gapers with slightly different art for their faces or Maggots that were a different color and just shot bullets when destroyed. The expansion added a TON of stuff like these, and the game was already big on "palette swaps" to begin with.
NT is the game that differentiates enemies the most.... but it also has by far the fewest of them, and it's likely to never have any more added past where they are now. Individual ones in that game took a VERY long time to make. The very low count of total enemy types in that game still remains one of my big complaints with it. And while they're differentiated very much in APPEARANCE, when it comes to FUNCTION.... they're very, very same-y. That one is THE thing that bugs me with that game. After the 10th enemy type that does literally nothing but try to crash into you, well, ya sorta get tired of it... and what few enemies there are that do shoot at you (without being IDPD), most of them have extremely simplistic shot patterns. Usually just variations of either firing a single bullet, or firing exactly 3 at once. And a couple that dont actually have a unique attack, but are simply firing shot types used by a couple of specific player weapons (Gators). There's certainly exceptions of course, but the variety is definitely a bit low in that game; fortunately it's set up in such a way where this doesnt actually matter all that much.
How about a survival room? There's a single invincible structure that creates enemies with its own life. After producing a certain number of waves, it dies.
I actually agree with the above posters though, the current "problem" with SR's variety is the inability to measure progress between floors.
There's a survival room coming. But the idea is that there's instead indestructible things firing at you constantly; you cant destroy them, so your only goal is to dodge and survive till time runs out and the things burst. Needless to say this isnt playable yet.
There's also one more new thing PROBABLY coming; I dont want to say what it is just yet, just in case, but it's a thing Chris has decided he really wants to do here, but it'll sure as heck be different than everything else. So there is at least something new probably coming already.