In a dark mountain pass Gordon explores a graveyard and gravekeeper's abandoned hut while escaping both Combine and zombie Headcrab forces. Boneshaker is a Half-Life 2: Episode 2 mod exploring this adventure.
Boneshaker is designed as a tense encounter taking place both in and outdoors, exploring some unique enemy encounter combinations. Players start out with only a crowbar and slowly amass more guns throughout.
The theme of this level is that Gordon is fighting through zombie forces until they stumble upon an abandoned hut. The hut is an old wooden gravekeeper's hut that has been ransacked and repurposed by the Combine to do experiments on zombies. After the hut, they start to see dynamic combinations of Combine and zombies.
For this level many of the encounters are ones not seen in Half-Life 2 or the episodes. I had to customize the behaviors and factions of most enemies in order to get them to behave appropriately to the player and each other. In several areas Combine and Headcrab forces will fight a three-way battle with you and each other. The number of enemies at times also scales depending on your equipment.
One important goal of this level was to set it apart from the graveyard area of Ravenholm in Half-Life 2. In Raveholm you fight alongside Father Grigori and against solely Headcrab zombies, with a strong emphasis on the Gravity Gun. Boneshaker is an isolated experience with tension built upon guns being given to you over time.
The layout of Boneshaker consists of generally wide outdoor areas with dim lighting that forces players to either shoot from lit safety, or explore more of the darkness and find valuables. Indoors, the encounters shift to more tight, cover based shooting. Paths snake around in an S pattern so you see your direct goal easily and early.
The level starts in a dark and open area with zombies idly stumbling about. Their only weapon is a crowbar to start and there is enough room to evade the small amount of enemies.
The cobblestone path represents the player's golden path, but if players explore outside it they may find guns, ammo, or health early.
At the top of a small hill players arrive at a shack. Combine soldiers pour out for a small gunfight after mowing through zombies. The gravestones in this area can be used for cover and some have ammo or items hidden by them.
The first room in the shack reveals the path ahead, blocked by boxes and computer equipment. This is a small rest area and boxes in here can be looted for more weapons and ammo.
In the next rooms the player engages in small gunfights with short line of sight. There exists both destructible and static cover.
Cover blocks the player's path in this area and must be used strategically as there is a weapon beyond it but breaking the cover leaves the player incredibly open for attack from one side.
After looping back to the first room the player opens a much larger and longer room which mixes zombies and Combine soldiers. Cover here is plentiful but it is not very efficient as it covers only part of the player. There exists a health and armor station at the end.
After leaving the shack the graveyard opens up much more and newer and faster enemies are introduced to the larger spaces. Zombines will relentlessly chase the player while Fast Zombies will leap from lower ground to reach them.
After the open area the path narrows to a much more linear direction. The lights darken and get fewer and further between. The zombie count starts to go down while ammo also does, stretching player's resourcefulness after larger area combat.
In the final stretch before the boss encounter several Zombine enemies chase down the player, wielding grenades to suicide into them. This last stretch is very tense and encourages fast forward movement.
To wrap up the final encounter the player is given a very large space to traverse, with tough enemies. Two poison zombies secure the area and soak up hits while throwing smaller poison headcrabs at the player. There are also a few normal zombies around to increase tension.