Space quest 4, the next game in the brilliant Space Quest series is a great adventure game. The first of the space quests to feature the point and click adventure mechanics, rather than text typing. I prefer the typing interface as I learnt how to spell English words by playing these games. The point and click games are fun, but do not help you learn as much as the typing games.
The game is all about time travel, through various Space Quest games, rather than years. It begins in Space Quest 12 where the dreaded Sludge Vohaul has taken over the world. Roger must survive long enough to find a time machine and save the day. This is a very exciting game where Roger travels through time visiting various planets such as the "Latex Babes of Estros". You even get to try your hand at making burgers at a Monolith burger to make a few buckazoids on the side, what a fun time.
No Space Quest game would be complete without the inclusion of an Astro Chicken mini game at the local arcade where you get to help pilot Ms Astro Chicken to freedom. I think the Sierra quests were some of the first games to include mini games like this. Today this is very common place.
If you have played Space Quest 1 VGA, you may remember that as you take off from the planet to attack the armada, another ship appears on the ground from which you took off. This is actually the time machine from Space Quest 4 and you get to visit Space Quest 1 while playing Space Quest 4! Luckily you don't meet yourself, so you don't cause a time paradox.
In summary, this is a good game to play, I would highly recommend playing any of the Sierra quest games.