6 points
JLPT N5 grammar points
ませんか vs ましょうか vs ましょうmasen ka · mashō ka · mashō
inviting, offering, and deciding together
は vs がwa · gafive tests that decide it, not one useless line
着る vs 履く vs かぶるkiru · haku · kaburuone English verb, and the body part that picks the Japanese one
に vs でni · dewhere it is, versus where it happens
ある vs いるaru · irunot animate vs inanimate — a taxi takes ある
熱い vs 暑い vs 厚いatsui · atsui · atsuithree kanji, one reading — use the antonym
One email on launch day
That's the whole list. rikAI is an iPhone app and it isn't out yet.