Construct2 can easily do it but you will need to get organized.
I would look into a sprite animator like Spriter for your characters. This would allow you to make all kinds of attack/block etc animations once you built the basic sprite parts for each character. Spriter also works with COnstruct2 and has its own event handlers... and you can usually find a bundle deal in Construct2 store for it.
The attack triggers like you mentioned are really easy.. simply make variables for each such as "SuperSmackDownPunch=0" and increment with each defined keypress (ie. SSDP triggers with keypress 1) so when user presses 1 it adds 1 to SSDP variable and sets a timer to set SSDP back to 0 after 1 second... and another event that listens for SSDP (or any other) to reach 4+ then fires off the attack if true...
AI is very doable as well with lots of tutorials on it.. So all in all.. I would say draw up an outline of what you need to accomplish and attack it part by part.
Hey, when you said variable do you mean instance, because I have it that when 1 is pressed, add 1 to Punchone. I tried a few things like set animation to punch1 and stuff, I'm kind of stuck, I know I'm doing something wrong, just can't figure out, how do you make it if 1 is added set the animation for a second or something, sorry, I haven't worked with variables in construct 2 a lot.