Once I got around to testing, I found that 1.1 had an issue where you could run straight up sloped tiles. 1.2 fixes it by checking a value at $09AE that seems to indicate you're standing on one, at the start of the new subroutine:
AD AE 09 LDA 09AE
29 00 10 AND 1000
D0 6C BNE end
