X-COM: Terror from the Deep

The Good
It's XCOM, more weapons, more missions, tougher enemies...

The Bad
EXTREMELY repetitive, some missions just too long and deteriorate into hunt-that-last-bug, much harder than the original, EXTREMELY tedious final mission, research tree "holes" almost impossible to recover from

The Bottom Line
After writing the XCOM FAQ, I received a preview copy of TFTD before the actual release. My initial impression after install is... This is XCOM with a new tileset.

After a bit of play, I realized that the difficulty level had been VASTLY increased. Instead of nice clean rooms with clear fields of fire, you now have lots of alcoves and deadends and corridors that makes for excellent ambush traps in all terrains (esp. those USOs, unidentified submerged objects). Lack of heavy weapons initially in the game makes terror missions EXTREMELY difficult (as most of your heavy weapons don't work on land). The two-part mission are pure murder on your troops with just too many places to search, and enemies often hold high ground before you can even deploy.

The addition of hand-to-hand weapons like thermic lance are interesting, but ultimately doesn't add that much to the tactical considerations.

This is essentially an expansion pack sold as a new game.