Its too easy and it is lacking progression(in units, possibilities and difficulty), that means after level 5-6 all levels are the same and once I got a clue levels became easier and not harder.
The game engine is nice though. You should maybe slow the speed of battles a bit down, so that manual control can make a difference. And a multiplayer mode would be awesome.
340k
sort-of-walkthrough:
1. Have a good start, if you cant affort 2 drills and one fuel after first round, restart.
2. Go deep.
Always try to go deep, one chest ist worth numerous coins and one big diamond is woth more than all other types together.
3. Get Trophies.
I got them all, once you have maxed out your drill, aim for the region with the desired type and get the trophies.
(a) Treasure and Coin Trophy, do a drive-by shooting, dont stick in that region on purpose
(b) Emerald and Ruby Trophy, on a run that brings you a nice bunch of them early stay in mid depth and try to grab the rest
(c) Diamond Trophy, all other runs should be made to get as many big diamonds as possible, so go deep on those runs and get the two diamond trophies by the way.
(d) 2600m trophy, make one dedicated run for it, you need a maxed ship, dig the first 3 levels, then use 3 boosts and at 2450m use the last boost. Collect everything on the way. A level 4 mole can clear rocks.