I don't know how useful this will be to people; with any luck it'll inspire some discussion. I've been playing a lot of Metroid-style games latel - Super Metroid (and a few Metroid ROM hacks), recent Castlevania GBA games, the Prime series. Metroid games, for those not in the know, are what I would classify as adventure/exploration games. The player is dropped into a large world with relatively little guidance (typically, just the overarching goal that they want to accomplish), and are free to explore to the limits of their abilities. New abilities can be found which expand those limits - for example, a double-jump to allow you to reach higher ledges, or a special weapon that can break down a certain kind of wall. What you have here is a glorified "lock and key" system, where the lock is an obstacle and the key is an ability needed to bypass that obstacle. One of the bigger dangers you can get into with this kind of game is turning it into nothing more than a set of "find the silver key to open the silver door"-type puzzles. This happens when the abilities you grant to the player do nothing except allow them to overcome some specific obstacle. A few concrete examples: 1) The "Heavy Ring" in Castlevania: Circle of the Moon (GBA) allows the player to push large blocks. These blocks are found in essentially two places: first, blocking the path to the next area after you get the ring, and second, as parts of puzzles much later in the game. The ability to push large blocks around is thus completely irrelevant except in that if you lack it, you can't get to the next section of the game. 2) The "Seeker Missile" upgrade in Metroid Prime 2 (Gamecube) allows you to "charge up" a set of missiles to fire onto multiple targets. However, it is rarely in your best interests to hit multiple targets at once instead of one target at a time, especially given the time required to charge up; the "real" use of this upgrade is to allow you to open specially-locked doors that require five ports to be hit simultaneously. There's also a boss where they help out slightly (Chykka, adult form), and an enemy that can likewise only be beaten by this upgrade, but otherwise, it is essentially purposeless in normal play. You're better off using normal missiles, which fire faster, or super missiles, which give more punch per shot and track better. Upgrades should be useful throughout the course of the game, not just in bypassing a handful of obstacles. Examples of good upgrades include mobility upgrades (e.g. double-jump, the ability to run, fly, or slide, and so on), new general-purpose armament (though this too can be done poorly; see below), or new armor. Mobility upgrades make movement smoother, thus improving the player's ability to get from point A to point B with a minimum of fuss. Sure, you could force them to re-play the jumping puzzle that's in the way, but they've already proved they can pass it, so why not give them a shortcut? New armor allows the player to worry less about enemies that used to be dangerous, because they deal less damage. Armament upgrades likewise allow the player to worry less about the minor enemies that used to be significant; if you can use one big blast to take down an enemy that used to require extensive duelling, then you'll spend less time on the annoying parts of backtracking. Now, new weapons, as I mentioned, can be done poorly. The biggest concrete example here is the new beams in Metroid Prime 2. You have the Dark Beam, Light Beam, and Annihilation Beam. The beams are needed frequently to open doors and to activate portals from the "light world" to the "dark world". That's fine. They also allow some interesting tactical decisions - the light beam can create beacons that are highly destructive to dark-based creatures, while the dark beam can freeze enemies (the annihilation beam is just destructive). That's good. However, all three beams require ammunition, and therein lies the problem. You, as the game designer, have just given the player a spiffy new ability and then said "Okay, now don't use it." Imagine how the player feels. The beams are not amazingly powerful, though they are significant upgrades over the basic beam. Ammo is sufficiently plentiful that the player can use the beams, if not freely, then at least frequently. But because the player now has to track use for two more ammo systems, the upgrades are less fun. Requiring the player to spend ammo to open doors, well past the point where the beams are acquired, is just rubbing it in. See, upgrades should be fun to use. The player gains power, allowing them to walk all over the old, annoying enemies. In contrast, you come up with new enemies and new areas to challenge them. In Prime 2, the player never really gets to walk all over his earlier opponents, unless he wants to spend a minute or two recovering ammo later on. As a result, when backtracking through previously-seen areas, they have to spend just as much time fighting off their opponents as they did when the area was still fresh and new. That's a problem. As near as I can tell, the only reason why the new beams require ammunition is because both the light beam and the dark beam are given to the player early on and are required to traverse most of the game content (see: activating portals from one world to another). What we have here is a poorly-designed lock with a key that thus needs to be reduced in power. The game would be more fun if the dark or light beam were given to the player later on with no ammo restrictions, as the player then gets to climb that power curve; however, the game world as designed requires both beams or neither is useful. One more thing - when you give an upgrade to the player, they should be thinking "Oh, cool! I can use this!" Not "Finally! There's that damned thing I need to proceed to the next area." This is going to be more a matter of subtly guiding the player from place to place than it will be one of choosing upgrades. As an example, the Super Metroid hack "Redesign" forces the player to run through a significant portion of underwater zones without the benefit of the Gravity Suit, which gives free motion underwater. Not having the Gravity Suit when underwater is very much not fun; mobility is vastly reduced and in general you can't go anywhere in a hurry. The original Super Metroid, in contrast, taunted the player with a few underwater areas that were inaccessible without the suit, but there were no underwater sections before the suit was obtainable. A similar philosophy applies to shortcuts. If you have a long, arduous jumping puzzle, put a shortcut on the end! You don't want players to dread some segment of the world because it requires the same set of carefully-timed jumps over and over again. Once they've proved their mettle, let them hit the "wave me through next time" button. In general, make certain that the second time the player visits an area, everything that was difficult about it has been toned down. Unless, of course, you're remixing the area (e.g. an earthquake occurs, changing up the terrain and loosing nastier enemies from their cells). In that case, the player is effectively exploring new terrain, and all bets are off. So when you're thinking about giving your player upgrades, make certain that the upgrades are actually useful. Ask your beta testers (assuming you've gotten that far) if a new toy was fun when they first got it, or if they just used it to figure out where to go next. Letting the player grow in power is not a bad thing; you can always scale the difficulty of later enemies to suit. Keeping the player from growing in power, in contrast, can aggravate them, as they end up feeling like all of the tasks they've accomplished have gained them no rewards. Find out what parts of your game are aggravating, and tone them down. Play other games in your genre, and figure out what they did well and what they didn't. Apply that knowledge to your own creations. Make a better game!

I notice you didn't have many complaints about Prime 1 - I found it was good about making old areas either quickly traversable (by getting, say, the plasma beam [grin] and double jump) or adding new challenges to them/reusing areas already cleared. I can understand your gripe about some of it, particularly new abilities that are used only to clear very obvious blocks and are useful nowhere else. However, I'm not so sure that keeping cleared areas difficult is a terrible thing. I've never played Prime 2 so maybe it just turned into an annoyance if you had to backtrack through the same area 10 times, but I don't think it's necessarily so bad for things to stay a challenge.

EDIT: This is so OT but have you seen how much sequence breaking has been done in Prime 1? I thought they were pretty heavy-handed about keeping things more linear than previous games, but people have done absolutely ridiculous stuff using bomb jumps and other creativity.

In the book Swords and Circuitry, Neal Hallford described what you're talking about as "Dead Squirrels" and "Vibrating Blue Squirrels".

Basically, a dead squirrel is a pretty much useless item that you have to carry around with you to complete quests in games, but is otherwise of little interest.

A vibrating blue squirrel is an item that is needed to complete a quest, but also has useful side effects that make the player want to carry it around with them.

I would argue that key items which are not useful except as keys should not be in the game. They're a sign that you have a weakness in your world design. If you have a key that only functions usefully in one place, why not remove the need for the key at that location? Allow the player to do things out of order if they so desire, and replace the key with an item that may not allow you past any more obstacles, but is useful in its own right (e.g. a health or damage upgrade). Not every item has to let you access new content. Some examples off the top of my head:

1) The Spazer and Plasma beams in all 2D metroid games simply make your beam weapon more powerful, and are never needed to open new areas.

2) The super-jump ability in Symphony of the Night. Bat form is a requirement to get it, so you can already fly; this just streamlines the process.

3) The aforementioned form upgrades in Symphony of the Night. You only need to get the basic Wolf, Bat, and Mist forms, but there's at least two upgrades for each that make the forms more useful.

4) Ammo capacity/health upgrades. Boring but still appreciated by the player, especially early on.

5) Any and all of the "sequence breaks" in the various Metroid games, most notably Super Metroid. Every single beam upgrade, as well as the Grappling Beam, X-Ray Scope, Spring Ball, Screw Attack, and I think even the High-Jump Boots xor Speed Booster are all optional, though most are apparently required on the first playthrough. This stuff is more for experienced players than for the people new to your game, but sequence breaks can add a great deal of depth (and therefore, replayability). Designing a game with sequence breaks in mind can be tricky, though.

This doesn't really relate to my point in the first post, where I was ranting about useless items that are required to get to new content. Here, these items are not useless and not required! They're just rewards for the curious, perceptive, or skillful players. Metroid-style games are supposed to be about exploration, after all, so there's nothing wrong with having "dead ends" in the world - that is, explorable areas that do not themselves unlock more areas - so long as the dead ends have something interesting in them. If every area of the game is required to be explored, then you've just taken the Metroid format and crammed it into a linear adventure game. Encourage the player to want to explore your world, but do not force them to.

Helix - it's one of my favorites too, which is why it's frustrating to see games which make (in my opinion) mistakes. The biggest two mistakes you can make with this genre are a) focusing too much on the "key" aspect of abilities and not enough on the "ability" aspect, and b) trying to limit the player's power level too much. I've already discussed the abilities-as-keys aspect, so I'll talk now about the player's power level.

These games are all singleplayer (though co-op could be done, I suppose in the Diablo II style), so limiting the player's power level just means that you end up toning down the difficulty of later zones. Why not reward the player with more power and then compensate by making the later zones more difficult? That way the player gets to enjoy his new toys and actually put them to good use. As a bonus, you improve the backtracking experience. Backtracking by its very nature requires the player to re-play content they've already seen. Unless something is different about the experience, it'll just become boring, like a cutscene you've seen before. As a game designer, you have two basic ways you can change the experience: change the player or change the content. I mentioned previously the possibility of having an earthquake that would change the terrain around and release new enemies into a zone; that's an example of changing the content. In that situation, the player is still backtracking, but they're effectively taking an alternate route through new content. This keeps the gameplay fresh and non-boring. The other possibility - changing the player - can be done in two ways. The first is the one you expect me to mention: make the player more powerful. Allow them to just run through the zone with a minimum of fuss. If you do this, then these parts of the game will not really stick in the player's mind, but then again, they also won't be nearly as boring as they could have been. The other option is to make the player weaker. You need to do this carefully, because players rarely like having things stripped from them, but you can set it up so that the first time the player visits a zone is the "easy" time, and the second time through is the "hard" time. This is essentially reversing the normal flow of the game, and can be quite interesting, if done well.

In my opinion, it's much better to make an easy game that has well-thought-out gameplay than it is to make a difficult game that doesn't. After all, the player can always set challenges for themselves to make the game more difficult. Castlevania: Symphony of the Night has an absurd number of ways to make the game harder, all the way up to playing a "naked" game (no equipment, no spells, only required extra abilities, punch everything to death).

Edit: Makeshift: I'm aware of the ability to regain ammo by using the opposing beam. Ammo was still not plentiful enough to allow free use of the beams. Compare: in Prime 1, once you got a new beam, it was used for almost all situations. The Wave beam was almost always better than the Power beam, the Ice beam better than the Wave beam, and so on. When the player gets a new beam, they get a clear boost in power. In contrast, Prime 2 does not give that clear boost. Even though ammo is available enough to keep you safe from running out in general use, it's not plentiful enough to let you use the new beams to the exclusion of the old ones.

[Edited by - Derakon on June 16, 2006 11:04:26 AM]