I haven't played it or anything, but this could still be a VERY early quick-port.
I remember playing a super early version of the Rainbow Islands: Towering Adventure port to XBLA from WiiWare and it was fuuucked. No menu system, the graphics were all off or showing the wrong tiles, it was broke.
I mean the game here only has the original 4 choices for the menu system - it doesn't have Achievements, Leaderboards, nothing. The fact that only Adventure is selectable and the others aren't looks like it's just the trial.