How should I balance buffs?
This can be a tricky area, as realistically, there are a lot of ways you can temporarily buff a players ability. There are some key points I can make, here, though:
- If a particular buff is considered to powerful, you may consider increasing the cost, instead of lowering the strength. If the buff costs too much, players will either save it for a rainy day, or use it freely and risk not being able to acquire another one for when they really need it.
- If you intend to involve multiplayer co-op, consider "support temporary buffs"; buffs that you can not use on yourself, but can greatly benefit other players. This works in supporting cooperation between other players.
- If a particular set of buffs in combination make your game too easy, make them mutually exclusive; if you already have buff a, taking on buff b will cancel buff a.
- Playtest, Playtest, Playtest. Have your testers fight the same boss or complete the same scenario without buffs and with buffs. Feedback should tell you wether the buffs made the game more playable or too easy.
- Balance Buffs with Debuffs. You have not said anything about debuffs, but in theory, your already implementing the mechanic; a debuff is really just a buff with a negative effect - if buffs make a particular enemy to easy to beat, consider giving the enemy their own debuffs to inflict on players to make the fight a bit harder.
What do players get out of temporary buffs?
I propose that players do not necessarily get fun out of the temporary buffs, themselves. Instead, the temporary buffs facilitate the player, to help them experience more fun from the game content.
Further to the fact; I personally find a direct correlation between my dependency on temporary buffs, and my opinion that the particular buff system is not fun. This might come down to my own opinion, or the types of games I play.
Temporary buffs can speed up game play
If temporary buffs make my character stronger, we can logically infer that the use of temporary buffs allows my character to kill the monster quicker. In turn, my character can kill more monsters in a minute with buffs, than they can without buffs. In games where the player might be killing a lot of monsters, this speeds up a process that is commonly not very much fun (i.e. "the grind").
As an example, World of Warcraft was once known1 for an excessive grind, and the ability to temporarily deal more damage simply meant you were leveling quicker, and grinding less.
Temporary buffs can make certain game play strategies possible
If temporary buffs increase the ability of my character, we can logically infer that there would be certain activities outside of my characters capabilities, that could otherwise be performed with the addition of a temporary buff. If the temporary buff makes the difference between doing something now or later, it can mean the difference between whether the player does it at all, or leaves it to later and forgets about it.
As an example, The Elder Scrolls is a game well known for its diverse character customisation, and includes a heavy "temporary buff" mechanic in the form of alchemy and potions. At certain points of the game, you may perform actions based off one of your skills; if the skill is to low, you have a poor chance at succeeding that "roll". The ability to quickly buff that skill for the purpose of the "roll" means that you can explore that avenue, even if you have not invested as much time in that skill, before.
Sometimes, temporary buffs may be required
It is not uncommon for game mechanics to require the use of a temporary buff. In turn, this adds complexity to the scenario, as the player needs to determine the right buff.
Although I am not as experienced with the game, The Witcher series offers a good example. At certain levels of difficulty, the game becomes nearly impossible without the use of correct buffs that compliment the required strategies and resistances when fighting particular types of enemies. Think along the lines of "I need to coat my sword in a temporary silver potion so it can hurt the vampire".
Temporary buffs are useful when I need to maximise my ability
This is provably exclusive to MMO games, but in certain games, "end game" content usually involves a race to become "the best". You need to make sure your character can put out as much damage, healing or control as possible, in order to give you and your team a running chance at completing the scenario.
In such cases, temporary buffs are almost a requirement, assuming they are available. If you can be fighting at 120%, why fight at 100%?
Lets be real, here. A lot of RPG games do use buffs, and if the player expects to be able to do something, limitations preventing them from doing so can break their immersion.
For example, there is no real reason I would want to down a hundred beers in World of Warcraft; but it pleases me that in doing so, my character gets drunk, my speech starts to slur and the screen becomes distorted.
This might be a lesser point, but I have seen it before, so it is worth addressing. Sometimes, buffs can be set up in a way that adds humor, instead of gameplay.
For example, there is a buff in The Elder Scrolls: Morrowind called "Icarian Flight", which temporarily boosts your acrobatics up to five times its maximum level. At such levels, your jump becomes so powerful that you can jump some of the highest mountains in the game - but if the buff wears off while you are still in the air, you will certainly die from the falling damage, when you land.
While this may have some benefit outside of humor, if used very carefully, I personally only found humor in this buff. To this day, it is one of my favorite examples.
How can I tell if others find the mechanic fun?
As addressed in comments, it is difficult to define fun. Everyone has their own opinions, because everybody is different. I can not stress this enough; do not fall into the trap where you insist your game is fun because you think it is fun - listen to your players, as well.
How can you listen to the players without releasing your game? Quite easily, if you employ play testing - which you should, at some stage.
- At the base level, ask your play testers. Play testers may not only be able to point out elements that are not fun, but may offer impression towards how you would draw out the elements that are fun.
- Data analytics. At the end of the day, if you can determine that players think a mechanic looks fun, but they never actually explore it, you must ask yourself why. Regardless, a fun mechanic that is never explored is ultimately not fun.
- Based off data analytics, ask your play testers, again. "We have noticed that a lot of players completely ignore the potion mechanics. What are your thoughts, in regards to the potion mechanics?".
- Once your ready to release your game, it should not stop, there. Ask your players for feedback. Provide a form they can fill out for any suggestions (and bug reports, though I digress), and more importantly, listen to your players. If once in a blue moon, a player submits feedback that "your buff system is bad, take it down", don't worry about it. It is foolish to think that you can please everybody, especially with as many aspects as which go into a video game. However, if you start to see a pattern, investigate. Perhaps a lot of players simply don't like the mechanic; you might consider an overhaul, or removing it, entirely. Perhaps a lot of players simply find the mechanic to confusing; in this case, your buff mechanic is not necessarily "not fun", its just to hard for players to get to before they can start experiencing the "fun".
1 Some may say it still is, but game play changes have severely weakened the "grind" required to reach a suitable level for decent content exploration.