The biggest thing the Vaal Temple is missing...

- A card that corrupts a room.
- A medallion that allows you to corrupt a room.
- The corruption chamber should be able to drop a currency that allows you to corrupt a room. Maybe a Vaal grenade that you use in the room similar to the Castaway explosive.

A corrupted room would not be able to be corrupted further, following the same Vaal rules.

You'd essentially be able to Vaal a room. Randomly doing one of the following
+/- effect (so maybe a 20% increased or decreased effect of the node)
+1 tier (this would be the only way to achieve +4)
-1 tier maximum (so this means 2 is the highest tier and tier 0 means it produces no effect but sits there anyway lol)