Looking around a little bit it doesn’t seem to have call with current continuation which is about the only thing that makes a Scheme implementation interesting. I’ve found implementing Scheme with TCO and call/cc is a useful way to compare languages.
PLAI is a good book for delving deep into that sort of thing.
Ugh, while I agree, call/cc is also a pretty demanding feature for compiler writers. If you somehow missed call/cc in the spec and noticed it a ways into your implementation, there’s a good chance you’ll have to rethink a lot of work.