Like in Naruto, some of the most powerful ki techniques are the visible ones. The Chidori and Rasengan were originally something of a spectacle because of the fact that ki is not normally visible to the naked eye. None the less, you have characters who display the ability to use ki in its more subtle forms, mainly in the characters who are mostly skilled in Taijutsu like Neji or Rock Lee. Through their skills they are able to use chakra to power their bodies to deliver strikes with speed, power, and accuracy. Their chakra remains invisible until they start using higher level abilities.
I feel like the Street Fighters Gen (or Yang) and Makoto make good analogies to Neji and Rock. Gen and Neji use quick kung fu-esque styles, that are focused on multiple precision strikes aimed to disrupt or shut down an opponents ki system. Makoto and Rock on the other hand both use styles that are comparably as quick, but are developed with the intention of being crushing and hard hitting. Rock being more influenced by Bruce Lee’s quick and fierce JKD, and Makoto’s style representing the quick hard hiting strikes of a karateka. This and the fact that although Gen and Makoto do not use techniques that regularly display visible ki, despite what their attacks infer about them being experienced with it.
Gen is most certainly familiar with the Dim Mak (点穴 “press artery”), as his Shitenshuu (死点咒 Shitenshū, “Death Point Curse”) from Alpha, and Shitenketsu (死点穴 “Deadly Pressure Points”) from SSF4 are basically a reference to this. He targets multiple pressure points which are vital for delivering ki throughout the body, and shuts them down in an instant. Of course this causes his victim to visually seizure and convulse.
A similar effect occurs during Zan’ei (慘影 “Cruel Shadow”) and Zetsuei (絶影 “Severing Shadow”). The difference being in this case he is targeting one vital pressure point and forcing his own ki through it (in the case of Zetsuei multiple times). Because the ki implanted is of a foreign nature to that of the victims, the energy itself will attempt to violently exit the ki system, disrupting and damaging it in the process. This too will result in seizure and possibly death.
Makoto of course has her Tanden Renki (丹田練氣・攻めの型, “Dantian Refined Spirit: Form of Offense”) which allows her to tap into her ki to deliver stronger attacks. A lot of her techniques are already devised with crushing power in mind, and some are visually targeted in areas like the neck, stomach, or groin. All of which are very vital.
I’m not sure if the characters are able to use ki to enhance their mobility on a foreign terrain. We know that extremely powerful characters like Sagat and Akuma have gone on record as being able to submerge themselves underwater for unnatural extended periods. Sagat can hold his breath for over 20 mins, and Akuma can survive for an unknown period in the pressurized depths of the ocean! These feats are more than likely capable through ki, as any normal human strong or otherwise would die under those conditions.
