ok this is probably borderline super noob, but I've still been learning inputs and I keep running into hitches in real matches. I just recently noticed that I can't button mash the light normals and expect them to combo. Does this mean the game has some built in anti-mashing mechanism that i should break free from when trying to combo?
Also, how do inputs work on wakeup? I've tried to do things like wakeup reversals with king but i end up getting up and just standing there without doing anything.
And one more likely silly input question, I can't seem to get the jump-ins for combos right... is there any secret trick that helps with that beyond perfect timing?
The game does not have any kind of mechanic which prevents mashing. Lets go over the two types of combos you can do with normals:
1. Links: When combo-ing light normals, such as cr. B x2 or cr. B cr. A, you are doing a link. This means that you have to wait until the recovery frames for your first normal to end before your second input will register. This means that links require specific timing. Mashing the B button still gives you many inputs, but if those inputs don't fall into the right time frame, your attacks will not combo. Combo-ing light normals is easier for some characters than others, depending on how much hitstun the normal gives you. For example, combo-ing cr. B for Leona is much easier than doing the same for Raiden. The more hitstun the normal gives you, the wider the window is for a link.
2. Cancels: When combo-ing any regular normal into a command normal (direction + attack), you are doing a cancel. A cancel is different from a link because you are actually skipping (or canceling) the recovery frames of your first attack into the command normal. This means that you have a very wide window to cancel, compared to linking. If you land the first normal attack and then just mash the command normal, most likely it will always combo. Keep in mind that this is still not a good idea for high level play.
On wakeup, inputs work the same way as in any other situation. However, the window of time to do a "reversal" or wakeup move is much smaller than it is in most other fighting games out right now (SF4, SFxT, etc). If you do the inputs too early, you'll stand up and do nothing. If this is happening, practice doing the wakeup move a little later. If you do it too late, however, you are leaving a gap of time on your wakeup when your opponent can hit you. Timing wakeup moves is simply a matter of practice, and is extremely useful. Wakeup uppercuts are great in this game for some characters!
One of the biggest changes to the console version of KoFXIII is that hitstun on jump ins have been decreased significantly. This means that combo-ing off of a jump in has become harder. To combo successfully, your hit has to land fairly low. This again is simply a matter of practicing your timing and spacing. However, some characters can combo off of high jump ins. To do this, you need a very fast stand or crouch B. For instance, King can combo off of a jump-in into st. B in some situations where she could not combo into st. C or D. Kula also comes to mind as a character that can combo into cr. B off of relatively higher jumps.
Overall, the issues you are having can all be solved with time, patience, and lots of training mode. Remember that mashing in this game is NEVER a good idea. One piece of advice I have for execution in general is to start by learning your character's full HD combo using 2 meters, starting with a hop-in. This might seem unintuitive, but learning the HD combo starting with a hop-in will teach you every aspect of execution with your character at once, and will be extremely useful once you start playing real matches. I hope this was helpful, let me know if you have any other questions!