Introduction
Gameplay Overview
Robert is a pressure/mixup/rushdown with long limbs and great control of the air as well. He has a couple key moves like his overhead and rapid kicks that allow him to pressure constantly in the corner. He is one of the better characters in KOF98 at guard breaks and accumulating stun (dizzy) damage quickly. His air and ground pokes have great reach as well, making Robert a very well-rounded and beastly character who falls just below the top tier. He's a great character for a beginner and doesn't require much more than average execution skill.
Combos
Robert has lots of combos, so let's get to work.
cr.Bx2 xx B Rapid Kicks (hcb+B)
cr.B,cl.B xx B Rapid Kicks (hcb+B)
cl.C/cr.C,f+B xx B Rapid Kicks (hcb+B)/A Ryuuko Ranbu (qcf,hcb+A)/A Fireball (qcf+A) (off cr.C or corner only)
cr.B/cl.B/cl.C/cr.C xx Kicky Throw (hcf+K), forward hh.D/f+B xx C Dragon Punch
[corner] cl.C/cr.C,f+A xx Dive Kick (qcf+K in air)
[meaty] f+A, st.C/A Dragon Punch (dp+A)
[meaty, corner] f+A, cr.B xx B Rapid Kicks (hcb+B)
[meaty, corner] f+A, cr.C/cl.C,f+B xx B Rapid Kicks (hcb+B)/A Ryuuko Ranbu (qcf,hcb+A)
[meaty, corner] f+A, cr.C/cl.C,f+A xx Dive Kick (qcf+K in air)
[pseudo combo] f+A (preferably meaty), Kicky Throw (hcf+K), forward hh.D/f+B xx C Dragon Punch
As you can see, he has a lot of combo options from a meaty overhead. From his kicks throw, f+B xx dp+C does the most damage, just make sure to get all both hits from the dp+C. To do this in the corner, try imaging f+B as a charge b,f+B move, and perform it right after the throw so that you move back a tiny bit. The hyper hop D can be replaced by other attacks, but hh.D sets up for a cross-under but running forward as soon as you touch the ground mid-screen.
In-depth Analysis
Normal Throws
b or f+C - Breakable, forward knockdown, face forward, rollable.
b or f+D - Breakable, reverse knockdown, back turned, un-rollable.
C throw preferred, since it doesn't have the blue grab 'effect' when it connects, which makes it harder to break on reaction.
Normal Moves
Standing A - Not that great for a standing A, can be anti-air vs short hop.
Standing B - Not bad medium range poke.
Standing C - Very good and fast long range poke, but some characters can crouch under it.
Standing D - Slower than standing C, but longer range, bigger hitbox, and only Choi/Chin can crouch under it.
Close B - Low and cancelable, like Kyo's. Great move to slow cancel into f+B (ie inputting f+B a little late to have it retain it's overhead properties).
Close C - Fast and cancelable, good as a meaty too.
Crouching B - Nice range cancelable (not chainable into command normals) low, the main poking tool into combos.
Crouching C - Very fast anti-air and ground poke! Cancelable. Not bad to slow cancel into f+A.
Crouching D - Medium speed long range sweep. Cancelable, and a good meaty. Good to slow cancel into f+A.
Jumping A - Crazy big hitbox but at a sort of weird angle. Can actually cross-up, too.
Jumping B - Can cross up, alright as a jump-in, but jumping D is better.
Jumping D - The tip of his foot on this poke tends to beat a LOT of things. One of the best air-to-ground 'poking' moves, or even air-to-air jumping back.
Jumping CD - Great air-to-air.
Command Normals
f+A - Best overhead in the game! Advantage on block, more advantage on hit, and a combo starter off a meaty hit. If it hits, you can go for a type of 50/50 with hcf+K throw or cr.B xx hcb+B. The meatier the better. Remember that you can delay the input off of mvoes chained into this to retain it's slower/overhead properties instead of just comboing. When chained, it combos from hard hits, is non-overhead, and cancelable into the Dive Kick (qcf+K in air).
f+B - Always the same speed and cancelable whether it's chained or done alone. Good combo filler, but never stop at this move as it is punishable on block.
Special Moves
Fireball aka Yooooou Big Chink(qcf+P) - C version stays out longer. A version is not a bad move to chain stuff into for safety/combo. Can beat certain things, like Choi flying at you. Just be careful, there is a blind spot in between Robert and the fireball, and if you whiff it you're going to get punished if your opponent has good reactions (or any reactions at all in case of the C version). Good as a meaty, too.
Dragon Punch (dp+P) - Yeah! It's a dragon punch. A version is fast and has a nice forward hitbox, but is not invincible at all. C version has upper-body invincibility only and doesn't knock down on the first hit, so use it as anti-air only. Good to combo off a meaty f+A mid-screen on the characters that can crouch under his standing C.
Rapid Kicks (hcb+K) - Use B version only! A move you will be using a lot. Safe on block, just beware of guard cancel roll. Advantage on hit. After it's blocked do more stuff! Learn your opponent's habits after blocking/getting hit by this move and fuck 'em up.
Dragon Kick (dp+K) - Like a dragon punch but with a little extra 'kick' to it *shoots myself in the head*. neither of them have invincibility, but they are pretty fast and sometimes a bitch to punish. I really can't tell if they are good or horrible. Some people like to use them in flowcharts when they think someone is going to attack. I personally don't like it, but experiment yourself to see if you do.
Dive Kick (qcf+K in air) - B and D versions are steeper/shallow angled respectively. Good for jumping back and punishing dps/things to get out of your pressure strings (Hellsap tactic). On block Robert flies waaaaaay back, but this move is punishable if your opponent guard cancel rolls forward. Good to be annoying with.
Kicky Throw (hcf+K) - Proximity unblockable. Invincible on startup. Fantastic tool for his mixups, especially after 'opening' (ie beating alternate guard) the opponent up with a f+A overhead. After an extremely meaty f+A in the corner it is hard to escape without risking getting hit by other things as well. You can juggle or reset after into more and more mixups. Sets up for whatever you want, a mid-screen cross-under, a meaty overhead/low mixup, etc. All the mixups are there.
Desperation Moves
Ryuuko Ranbu (qcf,hcb+P) - No invincibility. Just use the A version for combos. It CAN be used as anti-air, but it'll trade way more than you'll want it to. When it's blocked, shorter characters will crouch under some of the hits, bringing them out of blockstun. MAX version does more damage. All punishable.
Super Rapid Kicks (qcf,qcf+K) - MAX version is invincible, but that's it. Punishable.
Haou Shoukou Ken (f,hcf+P) - Super fireball! A version goes real slow, C version goes real fast. Good for the end of a match to just throw shit at someone from across the screen. The A version is a good meaty but there's aren't many places to use it (canceled from a f+B after Kicky Throw if they roll, or after a Ranbu hits) and it's not very advantageous considering Robert's other options.