A hidden feature in these Pokémon games is the ability to tell a certain NPC four specific words or phrases using the easy chat system in order to unlock special rewards. Which words are required are unique per save file.
In Diamond, Pearl, and Platinum these rewards include 8 different special PC box wallpapers. The NPC to speak to is located on the 3rd floor of the Jubilife TV station.
In HeartGold and SoulSilver, rewards include 8 different PC box wallpapers plus 3 different Pokémon eggs. The NPC to speak to is located in the Violet City Pokémon Center.

The original distribution of these passwords was via the Pokémon Daisuki Club, a defunct, Japanese-exclusive official fan club website.
Below is both a calculator to generate the passwords for your specific save file, an in-depth explanation of how the password check system functions, and a full dump of the relevant word data.
If you get stuck, comprehensive walkthroughs are available from veteran contributors on GameFAQs . Half-Life: Opposing Force
Opposing Force isn't just a mission pack; it introduces significant mechanics that evolved the Half-Life formula:
Even decades later, Opposing Force is praised by reviewers at sites like Force For Good as a "highly competent second helping" of the Half-Life universe. It adds depth to the lore of Black Mesa and provides some of the most challenging combat encounters in the GoldSrc engine. How to Play half-life-opposing-force-free-download-pcgamefreetop-net
Use specialized military gear like the M40A1 Sniper Rifle , the heavy M249 SAW , and strange organic alien weaponry like the Displacer Cannon or the Barnacle Grapple to navigate the environment.
You play as , a member of the Hazardous Environment Combat Unit (HECU). Your mission is simple: enter Black Mesa, eliminate the alien threat, and silence any witnesses—including Gordon Freeman. However, your transport is shot down, leaving you stranded behind enemy lines. Now, you must cooperate with fellow soldiers and even your former "targets" to survive the encroaching alien invasion from Race X. New Features & Gameplay If you get stuck, comprehensive walkthroughs are available
Opposing Force , tailored to provide a helpful overview of the game's features, story, and how to access it legitimately.
Experience the Black Mesa Incident from the Other Side: Half-Life: Opposing Force How to Play Use specialized military gear like
While the original Half-Life followed scientist Gordon Freeman, puts you in the boots of the enemy. Developed by Gearbox Software, this award-winning expansion remains a high-water mark for the series, offering a fresh perspective on the iconic Black Mesa disaster. The Story: Silent No More