So I uploaded a video of me playing CitizenSNIPS(TYM tourney player, really good Reptile) wondering if you guys could give any critiques:
http://www.youtube.com/watch?v=I2BVj608Veg
Alright I don't know much about Sindel but I've noticed some basic mistakes.
0:43 - You hit him with a cartwheel that sends him flying to the other end of the screen and he rolls back. Your reaction was to block here which was a big mistake.
When you knock someone down you have frame advantage and usually unless they have a very quick teleport you want to use that advantage to put something on the screen before them. In this case you should've taken advantage of that knockdown to start zoning. Either a low fireball or an otg one would've been good here. Even if he blocks them: you deal chip damage and build some meter so it's a win-win situation no matter what. So there's really no reason to just stand there and block. Think about it, what were you afraid of? Reptile can't even touch you with anything from there.
0:53 - Not sure why but you threw a low fireball even though there was clearly a force ball on the screen. You obviously were going to trade with that so it was a bad call. You should just block the force balls or jump over them.
0:57 - One thing I know for sure about Sindel is that she can make all her blockstrings safe. That F4, 4 you did, try to always end it with an air fireball. That would've allowed you to block his elbow dash and possibly punish him for it.
1:08 - I'm guessing you were going for a projectile there but dropped it. Anyway, what I want to point out is the range were you start round 2. That's the range were you should be expecting that infamous elbow dash from Reptile. So when you're around that range you need to back dash, jump back or block. You don't want to zone from there unless you have enough frame advantage.
1:13 - Smart use of D4 to space out Reptile. You can also use that poke to lower's Sindel's hittable box and avoid cross-over jump punches btw.
1:17 - You block Reptile's Elbow Dash but don't punish it. Reptile's dash is approximately -15 on block. Meaning all characters can punish it on reaction with throw or any normal/special that has 15 start up frames or less.
According to frame data, you could've punished his elbow dash on block with: 1,1,1 or: 1,1,b+2,4 because they both start up in 11 frames. Cartwheel could also technically punish it but you would need to be a jedi. Then again, even if Reptile blocked your cartwheel, at least you chip him and build meter + I believe it's a safe on block move though I'm not entirely sure about that.
1:21 and 1:28 - This is a mistake you often seem to do. You jump back and air fireball at the worst possible times (when Reptile puts a force ball on the screen right under you). The neat thing with Sindel's air fireballs is that they not only modify your arc jump but also lets you stay in the air longer. You should use that to your advantage to actually avoid his force balls and stuff.
1:40 - Reptile starts a combo on you but you didn't breaker. I'm guessing you were saving it for her X-ray but you should've known better.
You shouldn't be afraid to spend your meter on breakers. Since Sindel's strings are safe on block and since she is such a good zoner, you can build meter pretty easily and safely.