JSW64 allows more than the usual 4 cell types in a room. You could have two different colours of air, for example.
You can set the colour of Willy by room; you can also have crumbling floors in the style of Manic Miner.
JSW64 can have multiple ramps and conveyors per room, more than 8 guardians per room (not all variants), portals, and trampolines.
Features similar to those from Manic Miner include solar power and limited air.
John Elliott 18-4-2005