So I unpacked it and there's 2x MSI's for X86 and X64. But it looks like the download has changed because INNO SETUP always says it's not a valid installer. I've got the correct script, which downloads the file SSCERuntime-ENU. I'm trying to INNO setup to install SQL COMPACT as part of the install process.
Sql compact 3.5 sp2 download and silent install - sql-server-ce I don't think I'll get an answer to this one, because it's so obscure, but what the heck.