Never kill all bugs. Leave a fly there, so there will never be the next round of bug rush, unless you go across the cloud. In this way you can save time and focus on digging, and also save points because you don't need to upgrade blockage (I don't know its English name.....)
留一个小飞虫不杀，就不会刷新下一波虫子了，除非BOSS来了或者穿过云层。虫子永远不刷新，就可以安心挖矿，不用来回跑，也不用浪费时间在杀虫子上。而且也不用升级挡板了。

The secret room can be found in any cave, no matter its size. The fast way to find a secret room is going up right.
任何洞穴都可能有秘密房间，不管是大中小，最快的挖掘方式就是往右上方挖。

You need to collect five keys to beat the final boss. The first key can be found in the lowest cave. The rest keys are hidden in secret rooms of caves. There could be more than one key in each game. The fast way to collect all keys is going up right in the cave to find a secret room. There are three boss. The final boss is invincible, unless you put all five keys in the dome on the highest.
打败最终BOSS需要收集五把钥匙，第一把可以在最下面的洞穴里找到，其他的都是随机出现在秘密房间里。每一局不止一把钥匙。三个BOSS最后那个是打不死的剧情杀。

1. Shotgun is the lamest weapon. Drone may be useful, but it will eliminate all enemies, which lead to more and more powerful enemies.
2. Don't just go up or go down. If your speed is fast, you can collect all kinds of resource of all levels. I suggest you go down to the lowest and then go up.
3. Don't waste recourse on drone, turret. Focus on suit and gun. It is useless to kill enemies. The priority is sill finding secret rooms. So the suit is the most important.
4. It is very hard to kill the boss with gun, the only way is by missile.
5. It is a secret bug, I don't know if the developer can notice it. But the truth is, each time you go across the could, the game will refresh. All the things in the secret rooms will also be refreshed. It means that if you luckily found a secret room for a weapon or upgrade, after you go across the could and come back, you will find the room is sealed again and there is new weapon or upgrade inside! I use this way to collect all weapons and upgrades. Maybe I can use this way to collect all keys if I found a key room!

1、霰弹枪最垃圾，炮弹最好用，用了无人机的话会把所有敌人杀光，所以不太好。
2、不要只往上走或只往下走，优先升速度，就能多跑地方，收集所有资源。
3、不要浪费资源在无人机，炮台上，优先升级强能服，能大大加快找秘密房间的速度。这游戏杀再多的怪也没用，找秘密房间才是第一位的。
4、打BOSS只能靠导弹，所以别浪费弹药在BOSS上。
5、最好用的BUG，能用来刷武器，刷升级，不知道后续会不会改掉。就是每次穿过云层的时候，游戏会刷新，之前找到的秘密房间也会出现新东西。我就靠这个BUG刷出了所有武器和升级，不知道钥匙可不可以也用这种方法一次性全收集。