In the very first line of the song, with Len singing, it sounds like he's singing "kimi no naka." It should be kiri no naka.
Rin's first line, where she sings "isugiashi [de dekiru dake chikaku ni]" should be isogiashi.
"Asubi [wo hajimeyou]" (where they sing together) should be asobi.
Shinamon swaiku = shinamon sutikku (cinnamon stick); in the same line, "mahou no suchiki" = suteki.
Len's solo line before the chorus, it sounds like he's saying "terugai ni mamurarete"? Tengai ni mamorarete.
Right after that, it sounds like they're saying remuri ni ochiru? Not sure if it's actually remuri, but it should be nemuri if it is.
Rin: omoshirokunai deso = desho(u)
Can't tell what Len's singing in the second to last line of the first chorus, but it should be sono mi wo ima sugu ni.
yudanenasa saa = yudanenasai
Gonna go through the rest of the song really quick, sorry if it's unclear which lyric is what orz.
(Len) menzaifura wa sonzaishinai = menzaifu nado wa sonzaishinai
(Rin) nozukimita rantan ga = nozokimita rantan ga
(Rin, right after above) kage ni (...?)wazu = kage ni omowazu
(Len) warui ka omazame desu ka = warui ko omezame desu ka
(Rin) moumuku ni shiyou ka = moumoku ni shiyou ka
(Rin, right after above) waraunasai kawaii wo kau de = warainasai kawaii wo kao de
(Len) negawa wo mata kabutte = kegawa wo mata kabutte
(Rin, chorus) naka ni wo hairi (...?) wa totemo atatakai = naka ni wo hairi koko wa totemo atatakai
(Both) gensuku wo kanagurisute = gensoku wo kanagurisute
(Both, right after above) mutenashite amai mitsu wo sutte = motenashite amai (so on)
