TheFutureFlash
Noob
Red Hood is difficult to deal with because of his silly dash and his array of MB gun shots. He also doesn't have the best wakeups, but his b3 is pretty strong and covers a lot of ground. He has the mine so he can get a lot of mixup pressure if he gets you cornered, but he doesn't have the best tools to get out of the corner himself without an interactable. If you have to fight hood with Flash I think its good to go to a map where there isn't an infinite use interactable to allow you to leave the corner because it will make him easier to kill this way. Otherwise he will just dash to the corner, interactable out, dash to other corner, repeat (all the while spamming all kinds of gunshots at you).
Recently, Supergirl is pretty problematic for me as Flash ever since she got her recent buffs. She does great damage, and she seems to have answers for almost everything I try. She can zone you both in the air and on the ground with her lasers. The air ones are difficult because they really negate the RMS, making it harder for you to get in. If you switch to jumping in to get over the lasers, she tends to use the tele while you're in the air so you can' really block it. Once you do get close, if she is smart she will just d1 you first since hers is faster than flash's and reaches farther. You can try to get in the overhead, but its so slow that you are best taking a step back and trying to get in from there. She kind of controls every range and does just about the same damage as flash, if not more. She can get nasty combos in the corner and has good mobility in the air so she can advance on you and there isn't a lot you can do about it since she can also shoot lasers in the air and control that space too.
For Scarecrow I like to space it at the beginning since he doesn't have great full screen pressure. I find the spot where his long overhead chain move will whiff (f3?), and as soon as it does you can punish him with a combo and then back off (his wakeup where he blasts the green gas in front of him is, IIRC, fully invincible so best not to fuck too hard with that. Then he will try the long overhead again or use the tele, so as long as you are away and ready to punish, then he shouldn't be able to get in on you. He has a good neutral game and good reach on his specials, so it is a good idea to keep your distance and play more of a reactionary style. I think with Flash a lot of MU's want you to be the aggressor, but against scarecrow its better to let him come to you since he can just wait for you to get close and do the spinning chain move, or the long overhead chain, etc.
Recently, Supergirl is pretty problematic for me as Flash ever since she got her recent buffs. She does great damage, and she seems to have answers for almost everything I try. She can zone you both in the air and on the ground with her lasers. The air ones are difficult because they really negate the RMS, making it harder for you to get in. If you switch to jumping in to get over the lasers, she tends to use the tele while you're in the air so you can' really block it. Once you do get close, if she is smart she will just d1 you first since hers is faster than flash's and reaches farther. You can try to get in the overhead, but its so slow that you are best taking a step back and trying to get in from there. She kind of controls every range and does just about the same damage as flash, if not more. She can get nasty combos in the corner and has good mobility in the air so she can advance on you and there isn't a lot you can do about it since she can also shoot lasers in the air and control that space too.
For Scarecrow I like to space it at the beginning since he doesn't have great full screen pressure. I find the spot where his long overhead chain move will whiff (f3?), and as soon as it does you can punish him with a combo and then back off (his wakeup where he blasts the green gas in front of him is, IIRC, fully invincible so best not to fuck too hard with that. Then he will try the long overhead again or use the tele, so as long as you are away and ready to punish, then he shouldn't be able to get in on you. He has a good neutral game and good reach on his specials, so it is a good idea to keep your distance and play more of a reactionary style. I think with Flash a lot of MU's want you to be the aggressor, but against scarecrow its better to let him come to you since he can just wait for you to get close and do the spinning chain move, or the long overhead chain, etc.