i like it, compared to other games of this type you have a lot of time which greatly increased the fun factor of it, but the letters were too random and spread out, and it turn out a bit frustrating, there where points where i didn't have any buttons to use.
i was really having fun when i had about one or two buttons and had to constantly change their usage. if you are planning on improving the game i would suggest giving buttons a bit more durability and having only a few types, doesn't really matter what buttons they are as long as you can memorize where they are when you need them.
unlike other games with changing buttons this was really comfortable, great job.