What’s the minimum requirements to run the game?

Android 2.2 (FroYo).

Is there a tutorial?

No, but the first levels are quite easy so you can experiment and learn the game.

I’m an experienced tower defence player, do I have to play every level?

No, you can play the last unlocked level on each planet directly (see below for more information).

I think a level is too hard, what should I do?

You can replay earlier levels to gain experience and upgrade your skills.

The game information says there is 10 maps, but there is only 5 planets?

Each planet has 2 maps which it will switch between every 10th level.

Are the attack waves identical through out the game?

No. On the first planet/map they are about the same, but then they will be more randomized and new spaceships are added on each planet/map.

What happens if I don’t have the time to finish a level and quit the game?

You will keep the XP you have gained and the artifacts if you were lucky enough to find any. If you unlocked an achievement you will get the reward. You will however have to play the level from the beginning next time.

Is level 10 the maximum level for each planet?

No. When you’ve beaten level 10 on the last planet (Tarliak II) another 10 levels on each planet will unlock. Now you can play the planets individually. When you’ve beaten the new last level another 10 levels will unlock, and so on. In fact there is no maximum level.

How do I activate Endless Mode?

You have to beat level 10 to unlock Endless Mode. Then it’s available at the “Map selection screen”.
Note: you can only play Endless Mode on the last 10 levels you’ve unlocked. e.g., you’ve unlocked 50 levels on the first planet. Then Endless Mode is available at levels 40-50.