Overview
I bought Trias for one reason and one reason only - it has dinosaurs! I'd never played it before, but it seemed to get decent reviews, it's reasonably inexpensive (same price range as Carcassonne) and Evo isn't the easiest game in the world to track down. Several plays later, I really like this game and I'm glad I bought it (shallow reasons and all).
Each player controls one species (colour) of dinosaur and is trying to ensure that they proliferate as widely as possible as Pangea (the board) breaks up. This requires that the herds of dinosaurs spread out and reproduce as much as possible while avoiding drowning, overpopulation and being cut off from the largest land masses.
Thus, Trias is an area control game for 2-5 players with the added fun of a constantly changing map. I'd suggest that if you like Tikal, you're likely to enjoy Trias. Both games have similar "feels" - though Trias has more opportunity for direct player interaction. Trias is also similar to Carcassonne in that it can be played as a friendly family game (I'll just build up my herds over here while you split off a continent over there), but it can also be played cut-throat (oh, by the way, I just broke up your continent and stole two thirds of it).
Bits and Pieces
Be aware that many of the pictures in the image gallery include custom components or components from other editions. The English language second edition of Trias includes small wooden dinosaurs in a different colour for each player. They're all cut from the same pattern and look a little like stegosaurs. If you've ever played Ark, you'll recognize them:
The hexagonal tiles and scoring track are in muted shades of green, tan and grey - with dino footprints representing each position on the scoring track. The tiles are just under 2" (5 cm) across so that, when assembled, the starting board is only about a foot long in any given direction. Expect it to grow a lot bigger than that by the end of the game, though, as the tiles move apart! The game also includes two blue water tiles which are used to introduce random holes into the starting set-up and are removed before play begins.
It would have been nice if the game had included a play mat with hexes printed on it (as shown in the image below). 349
Presumably this would have required a larger box and may have increased the price. If playing with kids, I'd definitely download this player mat (http://www.boardgamegeek.com/fileinfo.php?fileid=14227) as it makes it easier to track how far any given tile is from the central volcano (South Pole tile):
The game does, however, come with turn summary cards for each player (though you do need to reference the rule book to answer questions like how to score) included in the deck of cards. The remaining cards picture one of the three terrain types with either a "1" or a "2" on the back. These numbers are necessary to control when the game ends as there is an additional "2" card that signals game end. Given the theme, this is, of course, the meteor strike card!
There's also an Italian edition of the game called Ciao Dino. Its wooden dinosaurs look more like plesiosaurs and its tiles are more brightly coloured:
How to Play
The rules below are for 4 or 5 players. For a 3-player game, three cards are removed; otherwise, it's the same as described below.
For a 2-player game, several tiles and cards are removed, each player is limited to 10 playable herds (plus one for the scoring track), the number of spendable actions is reduced from 4 to 3, and there's no midgame scoring.
Set-Up
Each player gets 16 wooden dinos - one for the scoring track; the other fifteen each represent one herd of dinosaurs. This is important to remember because it means that a lone herd can reproduce, doubling in size. You don't need two dino pieces on the same tile to reproduce!
The board is set up by placing the South Pole tile in the middle of the table and surrounding it with three rings of random tiles - making a large hexagon that is seven tiles across from corner to corner. Remove the two blue water tiles (leaving holes in the board) and put them back in the box with the two extra tiles you didn't use. This process means that you'll have a different board every time you play and gives the game most of its replayability.
Shuffle the "2" cards and place them face down then shuffle the "1" cards and place them face down on top of the "2" cards. 84