"Fusion: Genesis" was among the mysterious Xbox games rated in Australia and Brazil, the latter country specifying it as an XBLA title.A series of US trademarks found by Zunited reveals that whatever Fusion: Genesis is, it's probably part of a series.
In addition to trademarking "Fusion Genesis" (serial number 85277651, searchable here), Microsoft has filed trademarks for "Fusion Vault" (number 85277645) and "Fusion Sentient" (number 85277650), all specified as " Entertainment services, namely, providing an on-line computer game."
The three trademarks point either to some new "Fusion" series of XBLA games, or a single "Fusion" game with three potential titles that Microsoft had yet to decide on.