are the n-gage games playable on any of the N-series phones???

Not legally as the N-Gage game cards are copy protected and sold for use on the N-Gage or N-Gage QD only.

There have been mutterings about future devices supporting the N-Gage games i.e. standard handsets, rather than console handsets. At present though, the N-Series doesn't support this.