Forcefields in Spelunky 2 are a type of defensive barrier which prevents the player from accessing portions of a level, typically containing treasure.
Projectiles that do not have gravity affecting them, such as the freeze blast/bullets from a Freeze Ray or Shotgun will be sent going the other way, putting anything in front of it at risk. Thrown items (even with Pitcher's Mitt) and entities that walk into the forcefield will simply be sent slightly backward and downwards by the forcefield.
There are two variants of forcefields, with one deactivating and reactivating every ~3 seconds, and another that will remain activated indefinitely.
The indefinite version will appear in Dice Houses, only deactivating once the player rolls a 7 to allow them to collect their prize. Tun also uses an "airlock" system of two forcefields to block entry in/out of her challenges.
This variant of forcefield also serves as a blockade into pens of Neo Babylon, and as a defensive measure to stop the player from obtaining the Plasma Cannon or entering the Proto Shopkeeper pen in The Mothership. It can still be destroyed by a bomb, and forcefields in The Mothership can be disabled by killing Lahamu.
The deactivating and reactivating variant will appear guarding Lahamu in The Mothership and is a general hazard found in Neo Babylon that the player typically must pass through. The Sun Challenge also contains this type of forcefield, guarding the Arrow Of Light.As only the bottom block of the Forcefield generates it, destroying the top block will cause the forcefield to extend all the way up to the next possible block it can touch.
Forcefields periodically discharge vertical arcs of purple energy that deal contact damage and reflect any projectile or thrown object that collides with them, similar to the shield.
After two seconds of activity, the forcefield will shut off for four seconds before it can energise again.
Forcefields cycle automatically, and do not respond to the Spelunker's presence.
Forcefields will cease to function if their base conduit is destroyed by an explosion, so can be disabled by planting a bomb nearby while they are recharging.
TriviaDeath caused by rebound bullets show as "Death" with no explanation, just like when the Ghost kills you.