Here's a pretty good video on pacing. As for your question, mk.jr.fan, it is my opinion that having predictable difficulty curves ruins immersion. Even if the player doesn't know it, he or she will probably feel the predictability. This can be cool if you want to establish a pattern and then destroy it, making the player uncomfortable or excited, but overall I think it makes for a pretty boring game.

If you already have not, Punch Quest on the IOS is a great example of beat'em up game done right. All your suggestions already are in this game. Plus the game is free on the App Store. You will see what I mean.

The main thing to do is making all tactics that are trivial to devise, too easy to perform, or just ugly (spamming attacks, pushing against enemies and confiding in higher DPS, shooting with ample ammo, mashing buttons fast, herding enemies to hit multiple ones, and so on) obviously counterproductive, forcing the player to learn or lose.

For example, good attacks could work only in a limited vertical and horizontal range, forcing good positioning and making obstacles more important, and/or in certain enemy states (e.g. pull by the wrists and throw when the enemy lunges forward with a fist), forcing the player to really pay attention to what's happening.

The main thing to do is making all tactics that are trivial to devise, too easy to perform, or just ugly (spamming attacks, pushing against enemies and confiding in higher DPS, shooting with ample ammo, mashing buttons fast, herding enemies to hit multiple ones, and so on) obviously counterproductive, forcing the player to learn or lose.

For example, good attacks could work only in a limited vertical and horizontal range, forcing good positioning and making obstacles more important, and/or in certain enemy states (e.g. pull by the wrists and throw when the enemy lunges forward with a fist), forcing the player to really pay attention to what's happening.

I understand now that implementing the player to use strategy is important in gameplay but what happens when it can get overly complicated? Now after reading all of the comments thus far I do get the picture that in order to make a good beat'm up game is to give the player some difficulty so when the player wins that person would get a victorious feeling.

But my next question is where do we draw the line from where it becomes to complicated to learn how to play to making it an easy pick up and play game?

I understand that yes fighting games have lots of combinations in order to execute different moves, but keep in mind this is a side scroller beat'em like double dragon or teenage mutant ninja turtles for the arcade. It should be simple enough where the player can look at the control screen for like 10 seconds while the game loads and be able to do most attacks, but being able to have that satisfactory feel when s\he beats the game.

You could give the player really simple-to-use, but effective moves (for example: E. Honda's super-fast-palm-attack or Chun-Li's blurry kick-attack) to use to lower the bar-of-entry; giving players something to do other than just kick and punch, but don't make it the most effective strategy. Maybe early on it can get them out of trouble, but as the game advances the player needs to find other strategies (using bigger, but more complicated, moves; using the block/parry system; evading) to maintain that effectiveness. This can keep the game challenging while weaning the player off of the cheap-shot tactics and into the more advanced mechanics and exciting challenges that you want to throw at them. This might even turn casual players into die-hards (Street-Fighter 2 is a great example).

edit: found where this idea came from. Wow, I really do throw a lot of links to that show in this forum.

I understand now that implementing the player to use strategy is important in gameplay but what happens when it can get overly complicated? Now after reading all of the comments thus far I do get the picture that in order to make a good beat'm up game is to give the player some difficulty so when the player wins that person would get a victorious feeling.

Winning is less important than having fun playing, and cheapness (either on the player's side, because it is allowed and rewarded, or on the game's side, meant as a "challenge") is simply a sign of bad game design. The real "victorious feeling" is being aware of learning and improvement.

But my next question is where do we draw the line from where it becomes to complicated to learn how to play to making it an easy pick up and play game?

Don't confuse "difficulty" with having to play well, complicated rules with tactical depth, and easy to pick up games with simple and shallow ones.

A good game can be both accessible enough for newcomers to stumble through and complex enough to allow experienced players to perform much better.

I think you should first categorize the market, cuz at least the two major genres, casual and hardcore gamers, do not enjoy beat'em up games the same way, hence they'd judge good or bad differently. The responses above are majorly from the stance of a creative game dev providing a casual game to "real" gamers. If you ask Zynga or Kabam i'd imagine they give a vastly different aspect. I'm no specialist in this approach, but one of the reoccurring key to success is nailing the peak time of utility. Fun builds up doing repetitive experience, but after certain time unit, perhaps 30 secs, perhaps 3 mins, the curve enters marginal return phrase. If the game at that sharp moment calls an end to a gameplay or rewards a bonus / special event, then you raise the fun to the next level. its not the most "fun" project for the developer, and i know not all the truth but just partial truth about mass-public-mainstream-casual/social gaming.

Sense of impact!

All that matters to me is that when my character hits something, it feels like a true impact. It's part of the reason I love Marvel vs Capcom, and Smah Bros.

The perfect combination of sound, connecting animations and such, that for a moment really let me believe that something has smashed into something else.

What makes a good beat 'em up? Well, let's see:

1) Good controls. So you need a good format for them. Personally I'd go with about 7 buttons needed for a good modern day beat 'em up. I'll give you an example of them:

a) Punch

b) Kick

c) Block

d) Jump

e) Special

f) Grab - Nothing is worse in a beat 'em up where you accidentally grab when you meant to punch or kick. Intentional grabs are always good if you don't have a good system where you grab. SoR for instance has a good one, but say the classic Double Dragon? Not so much. This can also be used to stop the general confusion games have with attacking versus picking up a weapon. Now there can never be a moment where the player can attack the enemy

g) Back Attack - Because it's annoying to have it mapped on dual buttons.

The biggest thing that kills beat 'em ups for me is when you have limited controls and those are half the reason the game is hard.

For varied enemies, I'd say the big thing is to have something in mind for the enemies. For instance, take Streets of Rage, every enemy pretty much has some "specialty." Galza's throw you and do sliding tackles to knock you on the ground, Donovans are anti-aerial so jump attacks are less useful, ninjas land on their feet when you throw them and also have projectiles, boxers can block so throwing them is the best option against them... The biggest challenge is trying to exploit these patterns in various environments and various enemy formations. That's what makes it fun. The problem with so many beat em' ups is that the enemies you fight have no real rhyme or reason to how you fight them (or how they fight for that matter), so when you encounter another enemy you just approach it as a new punching bag.

Thank you for all the replies! After reading some I think I now understand how to make a game that's difficult, but fair. But also able to a have a variety of attacks to counter the enemy.

I do have one more question. For use of a keyboard what would be the best button combination for a beat'm up game?

My setup would be:

wasd: for movement

left Shift: to run

jkl: for action buttons

Is this a good setup or do you have any ideas of your own that you can add?