The scheme standard mandates things that are not in the wasm spec yet (tail calls and GC being probably the most notable ones, being available only in chrome).

The scheme standard mandates things that are not in the wasm spec yet (tail calls and GC being probably the most notable ones, being available only in chrome). There are quite a few open questions regarding RnRS schemes on webassembly. Currently it seems that the ones available are either discouraged by the limitations of wasm, or are implemented to specifically test non-standard proposals of wasm. In other words: no fun at all.