Though, there are many other instances in which the game seems to give Ryu i-frames for no clear reason, for example during the Izuna drop combos. Let's say, for example, Sigma 2, Master Ninja, Zedonius + gaja fight, DCTF. I approach a gaja, and I do STSSST. Meanwhile, Zedonius starts throwing fireballs at Ryu. The Izuna drop itself gives Ryu i-frames everytime and for the full duration of the animation, except (I think) a few frames during the recovery, so during that Ryu is always and completely safe from the fireballs. Though, the initial part of the combo, STSSS is supposed to have no i-frames. In reality, many times it happens that I just i-frames through the fireballs during SSS or during the launcher part, other times I get nailed.
Recently, a seasoned NGB/NG2 player told me that some moves in various ninja gaiden games give you i-frames on part of the character (like Royta was pointing out in the other thread here) but only if you are hitting an enemy with them. Basically they reduce the hurtbox of Ryu but only during hit frames. Now, maybe this may saound like a stupid or a lazy question, but... am I supposed to have some control over it or is just to make the game a bit easier to the player? Does a list of these moves exist? I'm sorry but it's not something that seem really easy to test in a game in which enemies can kill you in two or one hit so if someone has been less lazy than me I'll take full advantage of it
Also I've heard there are full frame data lists all over the internet... if you are not jealous about your knowledge, please share with me