I think this game would have been a hit if it had been released on a 3310 - really cool concept
My only major complaint is where the numbers show on the display - I found it confusing that the low numbers (1-5) were at the bottom of the screen, and the high numbers were at the top - it'd be a bit more intuitive if where the numbers showed up indicated to the player where they should be pressing on the keypad. Like if 1 is near the top of the screen it's easier to think "high number!"
This game was a but hard to play without a numpad, but as a fit for the 3310 it's great, I could definitely imagine people in the 2000's playing this on the bus on the way to school/work