Thanks, everyone. The First World just started a bit early in the particular universe.
Mechanics-wise it's really a lot the same. Same card driven turn sequence with special cards doing the same things. Same ranges and to-hits. Except now you roll lots of dice for shooting and close combat. Roll a die for each mini in the unit, halved if its shaken. Roll more hits than misses, target is shaken on top of casualties, which makes it really hard to do at long range, which makes sense to me. Roll more 1s than hits, the unit is low on ammo (roll half dice when shooting/fighting) until they spend a turn (or use 6) get some ammunition from the rear.
Contraptions and vehicle fit pretty seamlessly into it. I added some critical hit fun-ness and sustain rolls ala GASLIGHT. I was surprised how well it went. I could easily use the mechanics for other periods as well. Now, to MARS!!!!