This is a great trilogy and the price is unbeatable. The first Gobliiins game is quite hard because your little team shares a life bar and every injuring action empties it a bit. The problem is that doing the wrong actions is half the fun of these games. The goblins get hurt and the complain to you about sending them into these traps. It's hilarious.
Gobliins 2 gets rid of the bar and you can try everything out without worrying. You get 5 jokers in case you get stuck that will help you complete a screen. Especially the later levels require exact timing which can get quite frustrating.
Goblins 3 is by far the best part in the series. You get different partners with different abilities and all the puzzles are logical. The voice overs in the games are quite quirky, but they really fit the crazy characters and the overall funny tone of the games.
If you like adventures, you really shouldn't miss out on the Gobliiins. Too bad that Goblins 4 was such a let down. But if GOG gets Woodruff and the Schnibble of Azimuth, be sure to check it out. It's the unofficial sequel to these games.