Skill Levels

Skills make your character better at some aspect of the game.  Many unlock new abilities and new options for play.  Some are more useful than others depending on your goals for the game.

You can upgrade your skill levels by using stars.  The main methods for finding stars include:

* Digging: At certain depths, you will gain stars for digging that far down.
* Explosions: The first time you blow up a certain number of rocks, you'll gain stars as a reward.  You can gain these bonus stars for blowing up multiples of 5 (i.e. gain stars for blowing up 5 blocks, then 10 blocks, then 15 blocks, etc.).
* Cracked Sediments: You can find these, one at a time, typically closer to the surface.

The different upgrades available are described below:

Generally, this is a great starting upgrade tree to invest stars in. Save your gold and gems for the next tool (and their upgrades) but only save enough stars to unlock the next one, since it will usually take longer to get gold than get stars at higher levels.

It's an excellent upgrade tree to invest stars in, particularly after Drills are unlocked. Explosives are inexpensive in the mid-late game. The blast radius upgrades make a lot of difference. The water bomb is hands down one of the easiest ways to mine the magma.

A poor upgrade tree, compared to others. It's worth unlocking the Auto Shovel in general, and it can be worthwhile to unlock the Auto pickaxe on mobile or any version of the game that lets you view ads. The gem costs for later automatic diggers is too pricey to be worth it, though.

A useful upgrade tree, depending on your goals. If you play a version with ads, the gold magnet is worth getting (though it only lasts 30 minutes per purchase, which is possibly the worst thing to actually buy with gems). If you're in a hurry to rush drills and reach the end game, investing stars here will dramatically speed up how fast you get to the end. Otherwise, gold's not hard to make if you sell items so this can be skipped if you're not in a hurry.

A terrific upgrade tree. Both of the Push Power +1 Rock upgrades add significant quality of life, in being able to mine around and move rocks to stack up big chains to explode. The Slide Down Ladders upgrade is another "How did I live without this?" though the friction/heat up mechanic has to be watched. The last two upgrades also add nicely to your digging/mining power, making it easier than ever to mine the world without blowing through fuel.

Like the Gold upgrade tree, this can be useful depending on your goals. It's one of the cheapest skills to raise. Building certified lets you build your own walls as well as the crowbar (which is amazing for tearing down ladders if you want to drop a lot faster than an elevator can take you). Everyone should buy to level 3 - Steel Ladders certified as the Ladder Pack, while a bit pricey, is essential to not dying when you reach the magma level. Remember you can always crowbar back up your steel ladders, which gives them back to you.

Rock transformers will be 'set' by the first rock you roll through them. The next 100 rocks you roll through them will come out the same color.

Conveyers will 'push' any rocks that fall on them one space in the direction they're set in. If you put down several next to each other, they will push the rock all the way until there are no more conveyers.