Under rating threshold (hideshow)
definitely can be very good. Needs a little word.
Very hard to play with a laptop... (not that that is a bad thing)
I might suggest not starting with numbers so it feels more like a typing game... or atleast switch from numbers to just letters and maybe bring numbers back later. I really like the idea of using mouse with right and keys with left. Almost feels like a shooter...
Under rating threshold (hideshow)
This concept has TONS of potential. Add achievements, sure, bu the thing that matters most: ADD MUSIC. If you were to sync this up with music so that it was sorta like a sideways DDR thing, with letters, it would be pretty sweet. that, achievements, and some color changes with the music would make it absolutely fantastic. As for this, unfortunately, it's only going to get a 2 from me.