The idea is interesting, but it confused me a bit to be honest. There are some things that i'd like to mention.
The tutorial/ help screen: It's just too much text, it's usually better not to fill the entire screen with it, but to instead divide it into smaller sections. In example the section where you show the 1-5 keys is so crammed in there that you could not fit all of them in a single column, the 5 was on the top row to the right instead.
The objectives texts could also be separated into their own screen, and also it seems to mix story and objectives. Keep in mind this is what shows the player how to play, and you'd want it to be as clear as possible because you know how to play your game, but players don't until they go trhough this and try for themselves.
One last thing about the text, the font. H and K (also S and 5) look way too similar to eachother and this could cause users with smaller screens to having issues reading the texts properly.
The rest of the game is fine, but for me at least it looks too confusing, and since you don't have much time to react it ends up being a bit of trial and error. I don't think i've selected the proper thing even once, or maybe i did but didn't notice (obviously player skill affects this too), but here comes my next point: player feedback, something that tells you if you did it right or not. It can be a visual effect, a sound, a small text even.
It's not a bad game by any means, but the tutorial needs some work, specially since it's a type of game where you have to counter enemy actions in a short time period. The laser is pretty obvious when the enemy shoots it, but i've yet to understand what every icon of the enemy represent, and which is the appropiate counter for it.
Cheers, and i hope this helps. ;)