Nice presentation and an interesting idea! Turn based combo fighting game I guess? :)
I must say the instructions wasn't clear enough for me, as I thought that I need to press the keys simultaneously and the first like 5 rounds I was pretty frustrated that sometimes my attack/defense worked and sometimes not with no hint why that happened. Then after trying different orders of quick presses I realized what I supposed to do, but still sometimes I felt that I pressed right buttons quick enough, at least at the same speed as previous successful try, but this time I failed with no hint why. I think some visual timers and/or text hints like "Too slow", "Wrong combo" would help players like me to not feel frustrated :) Anyway in the end I was able to get the right speed I guess, and was able to beat the boss!