I don’t know if it would be so much fun, but I thought about having a Marathon mod, as an incentive to create great train lines to be able to complete the tiers. Maybe unlock train earlier.
Could be applied just to ingots maybe…
Aluminum Ingot
Caterium Ingot
Copper Ingot
Iron Ingot
Steel Ingot
Let me know what you guys think!! Thanks! 
I have run into something similar in Modded Minecraft, where the recipes are made much harder and more complex to craft.
To make it effective though would require features that I don’t know are implementable at the current time such as complete rewriting or removing recipes completely so you can only use modified versions.
Possible examples of a hard mode build:
Portable miner - organic parts (organic oil), gears, drills, crankshaft, mini storage box, etc …
Basic smelter - concrete, bricks, organic oil, bellows, gearbox, alloy frame, etc …
It’s completely possible to remove/rewrite vanilla recipes, several mods are doing it already
I had seen adding additional recipes but the base ones are still accessible in the system or is that just me? (This is across all the possible crafting methods, machine and manual)
Some recipes are blocked to change right now, but most of them we can change. We have to overwrite it and put the loading priority higher than the base game.
In the end i did this mod changing the recipe that the game not blocks…
It have 6 time the costs of raw materials for intermediate products/basic products
The changes (If you see some missing recipe, please, let me know)
Oil Pumps mines 6 times less crude oil.
(60 Cable) Recipe_HighSpeedConnector
(100 Cable) Recipe_SpaceElevatorPart_3 - Automated Wiring
(140 Cable + 30 Reinforced Iron Plate) Recipe_CrystalOscillator
(6 Reinforced Iron Plate) Recipe_Alternate_PlasticSmartPlating
(6 Reinforced Iron Plate) Recipe_SpaceElevatorPart_1 (SmartPlating)
(12 Reinforced Iron Plate) Recipe_Alternate_ModularFrame
(18 Iron Plate + 6 Iron Rod + 90 Wire + 12 Cable) Recipe_Beacon
(72 Iron Rod + 18 Reinforced Iron Plate) Recipe_ModularFrame
(30 Iron Rod + 150 Screw) Recipe_Rotor
(6 Iron Rod) Recipe_SpikedRebar
(312 Screw + 54 Cable) Recipe_Computer
(500 Screw) Recipe_ModularFrameHeavy
(336 Screw + 18 Reinforced Iron Plate) Recipe_Alternate_BoltedFrame
(36 Copper Sheet + 312 Screw) Recipe_Alternate_CopperRotor
(500 Screw) Recipe_Alternate_HeavyFlexibleFrame
(48 Wire) Recipe_Stator
(240 Wire) Recipe_Alternate_HighSpeedWiring
(36 Wire) Recipe_Alternate_Rotor
(12 Copper Sheet) Recipe_CircuitBoard
(30 Copper Sheet) Recipe_AILimiter
(66 Copper Sheet)Recipe_Alternate_CircuitBoard_1
(180 Copper Sheet) Recipe_Alternate_HeatSink_1
(30 Concrete) Recipe_EncasedIndustrialBeam
(54 Concrete)Recipe_UraniumCell
(132 Concrete) Recipe_Alternate_ModularFrameHeavy
(30 Concrete) Recipe_Alternate_EncasedIndustrialBeam
(18 Copper Ingot) Recipe_AluminumSheet
(12 Coal + 12 Iron Ingot) Recipe_Alternate_IngotSteel_1
(120 Sulfur + 96 Wire) Recipe_Battery
(42 Bauxite) Recipe_AluminaSolution
(18 Iron Ore + 18 Coal) Recipe_IngotSteel
(90 Iron Ore) Recipe_Alternate_CokeSteelIngot
(36 Iron Ore) Recipe_Alternate_IngotSteel_2
(30 Sulfur 30) Recipe_SulfuricAcid
(6 Coal + 12 Sulfur) Recipe_Gunpowder
(30 Coal + 30 Sulfur) Recipe_Alternate_EnrichedCoal
(12 Sulfur) Recipe_Alternate_Gunpowder_1
(270 Sulfur) Recipe_Alternate_UraniumCell_1
(18 Caterium Ore) Recipe_IngotCaterium
(12 Caterium Ore) Recipe_Alternate_PureCateriumIngot
(18 Raw Quartz) Recipe_Silica
(18 Raw Quartz + 30 Limestone) Recipe_Alternate_Silica
(30 Raw Quartz) Recipe_QuartzCrystal
(54 Raw Quartz) Recipe_Alternate_PureQuartzCrystal
(30 Uranium Ore) Recipe_UraniumPellet