Okay, I'd say NeoLemmix is ready to accept Cheapo input!
(Of course, not directly; it'll have to be first extracted with Essman's tool then run through a special conversion tool - both of which have yet to be made. Even after this, I suspect many levels will need manual touching up. But, it'll make the process a LOT easier. The point is; the NeoLemmix engine is now in a state of being able to accept converted Cheapo levels as close to their original form as possible.)
One drawback of the arbitrary one-way walls is that using actual objects for them would be almost impossible; rather, it just sets a one-way wall trigger area on the affected pixels, and hard-draws the one-way arrows onto the terrain there (it won't draw them in thin air of course, only on pixels that are actually terrain). The main effect of this is that the one-way walls set this way won't be animated. This won't matter much when using Cheapo styles, as the one way arrows don't animate there anyway; but for this reason I'll recommend continuing to use the objects rather than the arbitrary areas when making new levels.
For the record, it'll be (obviously) just as compatible with custom Cheapo styles as official ones, as long as they don't use any of the following types of objects:
- Triggered exits (these will work, but won't have the one-lemming-at-a-time effect)
- Two-way teleporters
- Single-object teleporters (teleporter and receiver in one)
- Splat pad
- Gravity changers
Additionally, levels with upside down entrances won't work properly (as NeoLemmix doesn't support inverted gravity).
Teleporters, Receivers and Anti-Splat Pads are fine; NeoLemmix supports the first two properly, and Updrafts are similar enough to the last one to replace them for most purposes.