Trespass is a member of a very small genre of games: asymmetric abstract strategy.
Asymmetric abstracts are not very common, with Hnefatafl and Fox and Geese being the only others that come to my mind. (I'm sure there are others, I'm just not familiar with them.)
In all of them, the players possess different pieces, with different properties from each other. Unlike most traditional abstracts where opponents have matching sets of identical pieces, with identical abilities.
In the box
I have the 'Trespass' version published by Lakeside Entertainment in the early 1980s. It consists of a vertical grid for a board, with yellow stickers marking the opposing goal lines for top and bottom, and playing pieces that are plastic 'plugs' that fit into the holes in the board.
One player gets the 'buffalo', 11 red pieces, while the other gets an 'indian' (white) and 4 'dogs' (black).
Buffalo can only move one space upwards, and only if the space in front of them is clear.
Dogs can move any distance diagonally, until they reach a board edge, or are blocked by an occupied square.
The Indian can move one space in any direction. The Indian can remove buffalo from the board by moving into their space. It is the only piece that can 'capture' in this game.
The buffalo player wins by getting a single piece beyond the top line. (into the top row)
The Indian player wins by capturing all of, or blocking the movement of the buffalo players pieces such that no more moves are possible.
The first few games of Trespass where pretty much just baffling. WHat is the best strategy for my side? Am I winning or losing? etc. It often seemed like either side could win, and there was no telling who was closer.
But after playing several games, I now think that the game is inherently tilted in favor of the Indian player. If he can stop the buffalo advances long enough to get his Indian into the lower swares of the board (which isn't that hard), he cap mop them up pretty quickly.
All in all, it appears to be a novel take on an abstract on the surface (and Lakeside's vertical board is cool), but it realy doesn't look to have much depth to it.
IF you are a fan of abstracts, at least one's with odd pieces, this might appeal to you. But if you looking for a deep, rewarding abstract, then keep looking.