Tested on a couple of boxes, games-fps/alienarena should be keyworded amd64..
post emerge --info please
kyle@localhost ~ $ emerge --info Portage 2.1.2-r12 (default-linux/amd64/2006.1/desktop, gcc-4.1.2, glibc-2.5-r0, 2.6.20-git14 x86_64) ================================================================= System uname: 2.6.20-git14 x86_64 AMD Athlon(tm) 64 Processor 3500+ Gentoo Base System release 1.12.9 Timestamp of tree: Thu, 01 Mar 2007 21:30:01 +0000 dev-lang/python: 2.4.4 dev-python/pycrypto: 2.0.1-r5 sys-apps/sandbox: 1.2.18.1 sys-devel/autoconf: 2.13, 2.61 sys-devel/automake: 1.4_p6, 1.5, 1.6.3, 1.7.9-r1, 1.9.6-r2, 1.10 sys-devel/binutils: 2.17 sys-devel/gcc-config: 1.3.14 sys-devel/libtool: 1.5.23b virtual/os-headers: 2.6.20-r1 ACCEPT_KEYWORDS="amd64 ~amd64" AUTOCLEAN="yes" CBUILD="x86_64-pc-linux-gnu" CFLAGS="-march=athlon64 -O2 -ftree-vectorize -msse3 -pipe" CHOST="x86_64-pc-linux-gnu" CONFIG_PROTECT="/etc /usr/kde/3.5/env /usr/kde/3.5/share/config /usr/kde/3.5/shutdown /usr/share/X11/xkb /usr/share/config" CONFIG_PROTECT_MASK="/etc/env.d /etc/gconf /etc/revdep-rebuild /etc/terminfo" CXXFLAGS="-march=athlon64 -O2 -msse3 -pipe" DISTDIR="/distfiles" FEATURES="autoconfig distlocks metadata-transfer parallel-fetch sandbox sfperms strict" GENTOO_MIRRORS="http://distfiles.gentoo.org http://distro.ibiblio.org/pub/linux/distributions/gentoo" LINGUAS="en" MAKEOPTS="-j5" PKGDIR="/usr/portage/packages" PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --compress --force --whole-file --delete --delete-after --stats --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages --filter=H_**/files/digest-* --prune-empty-dirs" PORTAGE_TMPDIR="/var/tmp" PORTDIR="/usr/portage" PORTDIR_OVERLAY="/usr/local/overlays/kports" SYNC="rsync://rsync.gentoo.org/gentoo-portage" USE="X acpi alsa amd64 ao audiofile bash-completion bitmap-fonts bzip2 cairo cdb cddb cdinstall cdparanoia cdr cli cups curl dvd dvdread encode exif fam ffmpeg firefox flac fortran ftp gif ginac glut gtk gtk2 iconv imagemagick imlib isdnlog javascript jpeg lcms ldap libg++ lm_sensors lua mad memlimit midi mikmod mmap mp3 mpeg mplayer msql mssql ncurses nls nptl nptlonly nsplugin offensive ogg openal opengl oss pam pcre pdf perl png ppds pppd python readline reflection ruby sdl session speex spell spl ssl svg symlink tcpd truetype truetype-fonts type1-fonts unicode usb vcd videos vim-syntax vorbis xml xorg xv xvid zlib" ALSA_CARDS="emu10k1" ALSA_PCM_PLUGINS="adpcm alaw asym copy dmix dshare dsnoop empty extplug file hooks iec958 ioplug ladspa lfloat linear meter mulaw multi null plug rate route share shm softvol" ELIBC="glibc" INPUT_DEVICES="keyboard mouse" KERNEL="linux" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LINGUAS="en" USERLAND="GNU" VIDEO_CARDS="nv nvidia" Unset: CTARGET, EMERGE_DEFAULT_OPTS, INSTALL_MASK, LANG, LC_ALL, LDFLAGS, PORTAGE_RSYNC_EXTRA_OPTS
Works for me as well. Portage 2.1.2-r13 (default-linux/amd64/2006.1/desktop, gcc-4.1.2, glibc-2.5-r0, 2.6.20-gentoo x86_64) ================================================================= System uname: 2.6.20-gentoo x86_64 AMD Athlon(tm) 64 X2 Dual Core Processor 3800+ Gentoo Base System release 1.12.9 Timestamp of tree: Fri, 02 Mar 2007 17:50:01 +0000 distcc 2.18.3 x86_64-pc-linux-gnu (protocols 1 and 2) (default port 3632) [disabled] dev-java/java-config: 1.3.7, 2.0.31-r3 dev-lang/python: 2.4.4 dev-python/pycrypto: 2.0.1-r5 sys-apps/sandbox: 1.2.17 sys-devel/autoconf: 2.13, 2.61 sys-devel/automake: 1.4_p6, 1.5, 1.6.3, 1.7.9-r1, 1.8.5-r3, 1.9.6-r2, 1.10 sys-devel/binutils: 2.17 sys-devel/gcc-config: 1.3.14 sys-devel/libtool: 1.5.23b virtual/os-headers: 2.6.20 ACCEPT_KEYWORDS="amd64 ~amd64" AUTOCLEAN="yes" CBUILD="x86_64-pc-linux-gnu" CFLAGS="-march=athlon64 -O2 -pipe" CHOST="x86_64-pc-linux-gnu" CONFIG_PROTECT="/etc /usr/kde/3.5/env /usr/kde/3.5/share/config /usr/kde/3.5/shutdown /usr/share/X11/xkb /usr/share/config" CONFIG_PROTECT_MASK="/etc/env.d /etc/env.d/java/ /etc/gconf /etc/java-config/vms/ /etc/revdep-rebuild /etc/terminfo /etc/texmf/web2c" CXXFLAGS="-march=athlon64 -O2 -pipe" DISTDIR="/usr/portage/distfiles" FEATURES="autoconfig distlocks metadata-transfer parallel-fetch sandbox sfperms strict" GENTOO_MIRRORS="http://distfiles.gentoo.org http://distro.ibiblio.org/pub/linux/distributions/gentoo" LINGUAS="en_GB" MAKEOPTS="-j3" PKGDIR="/usr/portage/packages" PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --compress --force --whole-file --delete --delete-after --stats --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages --filter=H_**/files/digest-*" PORTAGE_TMPDIR="/var/tmp" PORTDIR="/usr/portage" PORTDIR_OVERLAY="/usr/local/portage" SYNC="rsync://rsync.europe.gentoo.org/gentoo-portage" USE="X aac alsa amd64 berkdb bitmap-fonts blender-game cairo cdinstall cdparanoia cdr cdrom cli cracklib crypt cvs dbus deprecated divx dvd dvdr dvdread eds emboss encode fam ffmpeg firefox fortran gdbm gif gmedia gphoto2 gpm graphviz gtk gtk2 hal history iconv imlib java jpeg kde libg++ libsamplerate live lm_sensors mad midi mikmod mjpeg mp3 mpeg ncurses nls nptl nptlonly nsplugin nvidia ofx ogg openal opengl oss pam pcre perl png ppds pppd python qt3 qt4 quicktime quotes readline realmedia reflection sdl session smp spell spl sql ssl subversion svg tcpd theora threads threadsafe truetype truetype-fonts type1-fonts unicode usb vorbis wmp x264 xcomposite xml xorg xscreensaver xv xvid zlib" ALSA_CARDS="ali5451 als4000 atiixp atiixp-modem bt87x ca0106 cmipci emu10k1x ens1370 ens1371 es1938 es1968 fm801 hda-intel intel8x0 intel8x0m maestro3 trident usb-audio via82xx via82xx-modem ymfpci" ALSA_PCM_PLUGINS="adpcm alaw asym copy dmix dshare dsnoop empty extplug file hooks iec958 ioplug ladspa lfloat linear meter mulaw multi null plug rate route share shm softvol" ELIBC="glibc" INPUT_DEVICES="keyboard mouse joystick evdev" KERNEL="linux" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LINGUAS="en_GB" USERLAND="GNU" VIDEO_CARDS="nvidia" Unset: CTARGET, EMERGE_DEFAULT_OPTS, INSTALL_MASK, LANG, LC_ALL, LDFLAGS, PORTAGE_RSYNC_EXTRA_OPTS
Thanks, done.