A knowledge of smelting is useless unless you can generate the needed heat. If you don't have wood, you don't generally have charcoal, for example. On the "world ocean" you're not going to ever make TL 1 simply because fire is unobtainable in hot enough grades.
TL1 is use of metal
TL2 is the scientific method.
TL3 is steam and guns. Standards, too.
TL4 is electricity plus the ability to manufacture plastics. Interchangable parts, too.
TL5 is internal combustion and consumer electronics, plus fission weapons
TL6 is computers and fission power plants
TL7 can reach orbit, has consumer computing.
TL8 is system-wide capability, and commercial fusion, plus space life support long term.
TL9 is gravitics and jump drive,
The above is my synopsis from MGT...
Whole thing really needs to be reworked.
So, for TL 2, you need to be able to work metal, and have sufficient fire capabilities for steel. It's quite possible to lack sufficient or suitable plants in order to develop charcoal. At which point, also, metalworking past lead, gold, bronze and copper is probably out.
For TL3, you need materials with low coefficients of expansion, and reliable sources of metal. Again, it's possible to have worlds where metal is scarce enough that it's mostly in chemicals, but TL3 really is bogus based upon Mongoose's definition, unless there is no source of sulfer or saltpeter (which also pretty much precludes having terran compatible biospheres). In fact, gunpowder requires only ceramics and chemistry to make, and fire to be of use. And ceramics require no tools other than fire. Making the carbon requires fire. Wood canon have been shown to be doable (2006)... they require a boring spoon, but that can be bronze.
TL4 is electricity. Which requires TL1 metalworking, TL2 thinking, and a knowledge that it's good for more than just making a zap (TL0). Batteries require a pair of dissimilar contacts; one should be a metal, the other can be a metal or other conductor (eg carbon).. we can do those at TL1. We need vinegar.. TL0. We need ceramics, so we need fire. Magnets occur naturally, so it's possible to have TL1 electricity. Doing something useful is simple: Electroplating is TL1, as is electrosmelting. Hmmm...
The whole list is a problem, because there are many places on earth that can't make a bunch of stuff that they happen to have.
A locomotive, for example, requires the ability to roll out sheet metal, to make wheels turn, and to heat water. 90% of technology is JUST knowledge of process, and the process isn't that tech prerequisite... until you get to consumer goods ala TL4-5.
Firearms were made to standards in 1700... but without the right standards available, most parts were not interchangable, for example. Even though the knowledge was there (the standards were specified), they couldn't be applied accurately enough.