I turned on all the mod options. In prototypes/assembler-tweaks, both the .normal and .expensive are called out as nil values trying to start up. Removing the .normal and deleting the .expensive section allowed the game to start.

Could I get a mod list?

{
"mods":
[

{
  "name": "base",
  "enabled": true
},

{
  "name": "A Sea Block Config",
  "enabled": true
},

{
  "name": "angelsaddons-oresilos",
  "enabled": true
},

{
  "name": "angelsaddons-pressuretanks",
  "enabled": true
},

{
  "name": "angelsaddons-warehouses",
  "enabled": true
},

{
  "name": "angelsbioprocessing",
  "enabled": true
},

{
  "name": "angelsindustries",
  "enabled": true
},

{
  "name": "angelsinfiniteores",
  "enabled": true
},

{
  "name": "angelspetrochem",
  "enabled": true
},

{
  "name": "angelsrefining",
  "enabled": true
},

{
  "name": "angelssmelting",
  "enabled": true
},

{
  "name": "AutoDeconstruct",
  "enabled": true
},

{
  "name": "Automatic_Train_Painter",
  "enabled": true
},

{
  "name": "Better_Strand_Casting",
  "enabled": true
},

{
  "name": "blueprint_flip_and_turn",
  "enabled": true
},

{
  "name": "bobassembly",
  "enabled": true
},

{
  "name": "bobelectronics",
  "enabled": true
},

{
  "name": "bobenemies",
  "enabled": true
},

{
  "name": "bobequipment",
  "enabled": true
},

{
  "name": "bobgreenhouse",
  "enabled": true
},

{
  "name": "bobinserters",
  "enabled": true
},

{
  "name": "boblibrary",
  "enabled": true
},

{
  "name": "boblogistics",
  "enabled": true
},

{
  "name": "bobmining",
  "enabled": true
},

{
  "name": "bobmodules",
  "enabled": true
},

{
  "name": "bobores",
  "enabled": true
},

{
  "name": "bobplates",
  "enabled": true
},

{
  "name": "bobpower",
  "enabled": true
},

{
  "name": "bobrevamp",
  "enabled": true
},

{
  "name": "bobsflowcontrol-updated",
  "enabled": true
},

{
  "name": "bobtech",
  "enabled": true
},

{
  "name": "bobwarfare",
  "enabled": true
},

{
  "name": "Bob_Furnaces_Multipurpose",
  "enabled": true
},

{
  "name": "botReplacer",
  "enabled": true
},

{
  "name": "CircuitProcessing",
  "enabled": true
},

{
  "name": "EarlierLogistics",
  "enabled": true
},

{
  "name": "Explosive Excavation",
  "enabled": true
},

{
  "name": "FastRobotStart",
  "enabled": true
},

{
  "name": "Flow Control",
  "enabled": true
},

{
  "name": "FNEI",
  "enabled": true
},

{
  "name": "helmod",
  "enabled": true
},

{
  "name": "Hexy_AngelBob_Tweaks",
  "enabled": true
},

{
  "name": "Infinizoom",
  "enabled": true
},

{
  "name": "KS_Power",
  "enabled": true
},

{
  "name": "LandfillPainting",
  "enabled": true
},

{
  "name": "LightedPolesPlus",
  "enabled": true
},

{
  "name": "LogisticRequestHinter",
  "enabled": true
},

{
  "name": "LogisticTrainNetwork",
  "enabled": true
},

{
  "name": "LTN_Combinator",
  "enabled": true
},

{
  "name": "LTN_Tracker",
  "enabled": true
},

{
  "name": "MegaBotStart",
  "enabled": true
},

{
  "name": "ModuleInserter",
  "enabled": true
},

{
  "name": "Nuclear Fuel",
  "enabled": true
},

{
  "name": "OpteraLib",
  "enabled": true
},

{
  "name": "PickerAtheneum",
  "enabled": true
},

{
  "name": "PickerDollies",
  "enabled": true
},

{
  "name": "rso-mod",
  "enabled": true
},

{
  "name": "ScienceCostTweakerM",
  "enabled": true
},

{
  "name": "SeaBlock",
  "enabled": true
},

{
  "name": "SeaBlockCleanup",
  "enabled": true
},

{
  "name": "SeaBlockMetaPack",
  "enabled": true
},

{
  "name": "SpaceMod",
  "enabled": true
},

{
  "name": "Squeak Through",
  "enabled": true
},

{
  "name": "stdlib",
  "enabled": true
},

{
  "name": "UtilizationMonitor",
  "enabled": true
},

{
  "name": "WagonColors",
  "enabled": true
},

{
  "name": "ZRecycling",
  "enabled": true
}

]
}

It appears that Sea Block is causing this issue. I'm going to see if there are any other compatibility problems with Sea Block as I didn't really test this with that mod, and then update this mod. Thanks for the report.

I have somehow also forgotten to add compatibility with Bob's Enemies, leading to uncraftable alien artifacts. I am going to fix this too.

Now fixed for 0.17.2.

Thank you! :)

Just tried loading my game with the updated version.
migration_0.17.2.lua:45: attempt to index global 'mods' (a nil value).

Give me like 5 minutes and I'll have a fix for this out

Fixed in 0.17.3.