For anyone who still wants to complete the game in 2022 and can't get it to stop crashing, this might help:
'Back To Basics' is a mission in the second-to-last where most players will first encounter Slimy Slugs. On my device, deploying Sonic Blasters against them would consistently crash the game. Even after implementing a community fix.
You can find tips on the forum to stop them from spawning by keeping your crystal count below 15. I tried to do this by spawning tunnel scouts to bank my Energy Crystals but ended up crashing the game again. Another method is to turn off buildings they try to drain, as their ability only works on buildins that are activated and receiving power.
Using this knowledge, I found another way to reliably stop slugs from appearing near your base: Slimy Slugs are not allowed to pass through buildings or climb walls. Blocking off their holes with buildings off the power grid prevents them from doing any harm. I used Small Teleporters for this, but someone should test tool stores as well.
In the 'Back to Basics', most of the holes in the cavern you start in are near a wall. This means you only have to build two buildings to completely wall of these holes. Some of the holes are hidden and you can prevent these from activating by not opening up the caverns these are in.
I ended up building a Support Station, then an Ore Refinery, and then building all the teleporters. Figuring out where to put the power paths and teleporters can be a bit of a puzzle in the limited space.
You may have to destroy power paths or even relocate buildings to ensure that the teleporters are not given power.
I really should have tested if turning the power off on those teleporters is enough to stop Slimy Slugs but I really wanted to do the mission quickly to prevent more crashes.
If you used this strategy properly, Slimy Slugs will spawn on the holes but they are unable to move away from this tile. Their number will increase as you collect more crystals.
The slugs prefer holes close to your base but you may end up opening caverns further away where they can spawn. If that happens, you will either need to block those off as well or rush to complete the mission before they can crawl to your base. I ended up doing the latter. So while this may not be foolproof it does allow for a margin of error when otherwise you would have no way to even slow down the slugs after collecting a certain amount of Crystals.
You can build a new Tool Shed and destroy the old one or even destroy the Ore Refinery to force Rock Raiders to use materials nearby the farwaway building site.
Rock Raiders with Blasters have a good chance to kill the Slimy Slugs if they are far away but the presence of other Slugs on the map may prevent them from targeting slugs that are roaming free.