We thought about enabling the keypad (actually the first builds had it working), but it was too easy to play. Dexor (the programmer) wisely decided to make it mouse only :) .
Yup, we should have added some audio or visual feedback for when the keys switch, but it's alright I guess :D .
By the way, the click sound was recorded with by myself (like all the other sounds) lol. What you hear is my mechanical keyboard, haha. Glad to hear you liked it.