You can do a LOT of amazing things with seppukuties, the level editor is really incredibly flexible. However it's not perfect, and there are certain things that it just won't let you do. That doesn't necessarily mean that those things are impossible to do though.
As it turns out, every seppukuties level text code is not encoded at all. This means that it is possible through experimentation to piece together what each individual letter and number in that character string means. This also means that you can directly modify the code, sometimes even breaking rules that the Seppukuties level editor enforces.
Well, it'll be easier to just show you:
Factory - Avg Time: 25 seconds, Par: 1(0 possible), Acorns: 0
Challenge - Key Timing, Jumping Accuracy
31B2AB28HB2AB28HB2AB28HB2AB28HB2AB28HB2AB28AB2AB28AB2AB15A12B AB2AB28AB2AB28AB2AB17A12B2AB28AB2AB28AB2AB15A12BAB2AB28AB2AB 28AB2A30BAX2CEDAEDA2J2ABAB2C6ABDBDBA2EA2B2A3BA2BDB3A4CIAEJACD 2ABCBDC6A4CEAEGACG2ABDBAC6ACEJDHACGABJ2ABE9ACEJEDAEJABJ2ABF9A CEJEJACGABJ2ABG9ACEJ2FADJABJBFBH9ACEJG2ACGABJ2ABI9ACEJHDADJAB JAFBJ9ACEJG2AEBABJAFC10ACEJH2AEHABJBFCB9ACEJH2ADFABJBF2C9ACEJ HDAEFABJAFCD9ACEJDHADHABHAFCE9ACEJDHAEDABHAFCF9ACEJ2FAEFABJBF CG9ACEJFIACGABJ2ACH9ACEJCDADBABJ2ACI9ACEJCFADBABJ2ACJ9ACEJGCA GDABF2AD10ACEJHBAGDABF2ADB9ACEJGJACGABJ2ADC9ACX14034036034031XFactory@Grey#Acumen
Currently wrapped up in: Half Life, Portal, and User Created Source Mods