this may be outside the scope of your project but adding a few emulators can give you thousands more games...
Dosbox with dbgl provides a really easy way to play DOS games - "Another World/Out of this World" is a great DOS game... Also Civ II, many others...
But like many DOS games, they are better on the amiga. For amiga you can use various versions/forks of UAE...
There are some packages here: ppm.scottjarvis.com (see Emulation section)..
..some of these old games are honestly classic, very playable, challenging and great fun.
BTW, 'cave story' is still one the best little platformers on linux , you can get a patched/updated version at akita.scottjarvis.com .. And I do recommend xrick...
EDIT: I forgot, XSok (xsokoban) is a classic puzzler, it's TINY, very challenging, has many levels, and includes a level editor (well, can edit the level files, anyway!).
Also in the akita repo, gnu-go/cgoban are popular, old chinese board game progs... And xboard is a good chess frontend, forget the backend I used (fairymax?), but it's the lightest, and it's included in the xboard .pet. (i think)..
just for completeness, and so you dont have to trawl through them yourself, here are all games in the akita repo:
(you can search the
livepackages5a.txt file in the repo for descriptions, sizes, etc)
akita_games-0.1 <--- includes many little games, inc good cli tetris
assaultcube-1104-akita
assaultcube_reloaded-240-akita
biniax-1.2 <--- odd but good puzzler
braincurses-0.5b-i486-akita <---- cli mastermind thingy
BubbleSnooker-1.2-akita
capitalism_0.5.1-i486 <--- monopoly board game
cartoon_fighter-1.1-akita
cave_story-1.2-i486-akita
cboard-0.6-i486
cboard_DOC-0.6-i486
cgoban-1.9.14-i486-akita
cgoban_DOC-1.9.14-i486-akita
dbgl073-i486-akita
digger-20020314-i486-akita <--- classic, but smaller versions are around
dosbox-0.73-akita
dudusdl_0.1.3-1_i386-akita
eDuke-1.4.0-i486-akita
epic_inventor-i486-akita
epsxe-1.6.0-x86-akita
epsxe-1.6-akita
fairymax
flash-chess
freeciv-2.3.4-i486
freeciv-2.3.3-i486
freeciv_DEV-2.3.4-i486
freeciv_DEV-2.3.3-i486
freeciv_DOC-2.3.4-i486
freeciv_DOC-2.3.3-i486
freeciv_NLS-2.3.4-i486
freeciv_NLS-2.3.3-i486
freecol-i486-akita
freecol_DOC-i486-akita
freecraft-1.20-static-20120816
freecraft_data-1.20
gens-2.15.5-akita
gens_gs_r7-i486-akita
gens_gs_r7_DOC-i486-akita
gnuchess-6.0.1-i486
gnuchess_DOC-6.0.1-i486
gnugo-3.8-i486
gnugo_DOC-3.8-i486
greyhounds
gsoko-0.4.2-akita
gsudoku-akita
gtkatlantic_0.4.2-3_i386
jester-1.0
JNKPlat-20100420-akita
king_arthurs_gold-190-akita
lbreakout-010315-i486
liboil-0.3.16-q1
lugaru-rev269-akita
lxdream-0.9.1-i386-akita
nethack-3.4.3
newton_adventure-1.3-akita
numptyphysics_0.2-akita
opensonic-0.1.4
openttd-r22274-i686
openttd-r22274-locales
operarena-2006-akita
pacman_cli-1.2-i486-akita <--- good little pacman game
pacman_X11-1.0-i386-akita
pcsxr-1.9.92-1-i386-akita
pingus-0.7.2-akita
pipepanic-0.1.3-i486-akita <--- very addicitive to beat score (i think!)
pSX-1.13-akita
quarry-0.2.0-i486-akita
racer-054
rocksndiamonds-3.2.3-akita <--- digger clone
rubix-1.03
Scrabble3D-i386
scratch-1.4.0.1-i386
seahaven
seatris-0.0.14-i486
seven_kingdoms-2.14.3-akita
snes9x-1.53-akita-i486
snes9x_NLS-1.53-akita-i486
soulfu-1.5.2
starfighter-1.2-i486-akita
starfighter_DOC-1.2-i486
stormbaancoureur
supertuxcart-0.6.2-i386-akita
tileracer-0.702-0-akita
touchmegames-0.2.5-i486
ultimatestunts-0741
vbam-svn451-1-i386-akita <--- gameboy/gbadvance... mario golf, advance wars, many other classics!
xarchon-0.5.0-10.2-akita
xasteroids_5.0-17_i386
xboard-4.5.2a-i386
xemeraldia-0.4.3-i486
xgalaga-0.8.1-akita
xinvaders-2.1.1-i486
xrick-021212-akita
xsc-1.5-i486
xshisen-1.51-i486
xsok
xsoldier-1.4
xsudoky-1.0.6-i486
ysflight
zepsdreamland-1.02
zombiegrinder-323-akita