The original Titan Omega featured;

-5 Game modes
-360 weapon combinations in Omega mode
-12 large levels
-4 NPC Team pilots
-Multiplayer mode
-3 Save slots
-4 Difficulty modes, each with a range of unlockable extras
-Large story with references to religion and myth. All explained in...
-Cut scenes! Starring 4 characters each with his/her own personality
-Unlockable version of the original Titan Exodus, recompiled for speed

Titan Omega 1.5 already features;

-Massive bug fix. All known bugs fixed (!!)
-Speed increase, in more ways than one
-Health! Can take up to 5 shots
-Ballistics! Every so often a giant explosion of lasers helps clear the screen
-Checkpoints
-Lengthening of levels
-More dynamics and graphics in levels
-New! sub-tasks for each level
-13 much bigger levels
-Briefing scene prior to level
-Ranking system (level complete screen)
-Rock-solid  encryption system
-All difficulties open from start
-Shop for team
-Speed level-ups, after so many bad guy kills
-Support for 4 button Joypads
-Team Command system
-Huge Team AI boost, and they're more aggressive too!
-Huge update for 2 players! You can now upgrade your buddy in the Team Shop too
-Alternative ship modes (Change from 3 sets during game play)
-New mini-weapons! collect these powerful beauties on level for a short but destructive spree
-New bosses!
-New "Minimode" extras
-New artwork in cut-scenes and intro animations
-New explosions
-Few new weapons
-Ultra Quality graphics mode
-Story is much clearer
-Lots of new enemies
-Easier and faster game experience, except Hero mode ;)
-Slowdowns almost totally eradicated barring a few really heavy battles (object limit kept down, waaay down compared to the original)
-New launcher which supports resolution changing in window mode

Things that MAY make it into future versions;

-Online/LAN multiplayer
-4 Players
-More items in Team shop
-Team ballistics

Things taken out;

-Secret Cazza mode
-Lives, the bane of higher difficulties! Makes it easier again
-Unlockable TE
-Bugs :( ill miss all them glitches