It's not like Tikal and in fact is quite different. Only the theme is related, and it was a marketing decision. In Tikal II, players are archaeologists excavating a newly discovered Mayan temple. They explore rooms, collect treasures, and do all sorts of stuff to gain points. Most points at game end wins.
The game is played over two halves. Some scoring is done during player turns. Major scorings are done at mid and end game. On a player's turn, he picks one of the action tiles laid along the edges of the board, and then uses his explorer character to do one excavation. These action tiles drive the game, and trigger the end of each half.
One important concept in the game is the keys, of which there are 5 colours. You need keys to go through doors and explore the temple. You also need them during mid and end game scoring. The tricky part is when you gain a key, you must immediately decide what to use it for, and once that's decided, you can't switch. You need to decide between mobility and scoring.
As rooms are discovered, tiles are added to the board. Some rooms reward only the first player to excavate in it, some offer multiple different rewards, and of course the earlier you excavate the more choices you have. When excavating rooms you are rewarded for rooms of the same colour that you have excavated before, so it pays to specialise.
If you collect treasures, you can time to sell them at certain times when you pick an action tile. Timing is important because the values of the five types of treasures fluctuate, changing each time a sale is made.
There are cards you can draw, some giving special abilities, some scoring at game end.
I played a full 4-player with Jeff, Allen and Henry. I decided to work on treasures, and picked many such actions. Not many other did this, which allowed me to time the treasure values more easily. However Allen did do some, and for a few batches of his treasures he sold them just in time before I could, and devalued my treasures. Aarrgghh...
Most others used keys more for access and less for scoring. I tried to resist this and tried to commit more keys to scoring. It did restrict my mobility somewhat, but I compensated by collecting some secret passage tokens. These one-time-use tokens allow you to enter rooms that you don't have keys for, even rooms without doors.
Allen excavated many pink rooms, which gave him lots of points. No one else spent much effort on specialising in a particular colour. Allen took the lead and eventually won the game.
I expected the game to be so-so, and I indeed found it to be so-so. Is it a self-fulfilled prophecy? Many say one improvement over Tikal is you only choose one action tile and do one excavation, as opposed to having ten action points which can be used to do many different things. I'd call this a difference, not an improvement. They are simply different games.
I feel the game is unfocused. There are many different things to do, and the feeling I get is they are rather loosely related. Many just happen to be on the action tiles that you pick. The cards feel disjointed and unnecessary. The secret rooms outside the temple feel like they are there to give purpose and to give more use to the secret passage tokens. In Tikal, all the different actions are geared towards only two things, temple scoring and treasure scoring. I actually find Tikal easier to learn, because it makes more thematic sense and is more coherent.
I probably shouldn't be comparing Tikal II with its predecessor. They are different games that should be assessed on their own merits.
Tikal II is a pleasant game to play. No direct confrontation, not many nasty moves you can pull on your opponents, you'll rarely get stuck with nothing better to do. The production is definitely top-notch. Too bad the game isn't very captivating.