One simply cannot create a game with placing/breaking blocks, time travelling, time paradoxes, crafting system and sandbox genre with an end goal. But I did. Kinda.

What the game’s about?

Planet rescuers is a sandbox-style game, where you play as a robot who was departed to an unknown planet with a time travelling machine. Your mission is to change future in order to get rid of strange creatures who will cause some problems.
Gameplay: You can break and place blocks in a 2D world. In the center of the map there’s a time machine which can send you to the future or to the past. The block that you placed in the past will stay when you’ll go back to the future. Metal will rust, trees will grow. Look at this comparison picture:

But if you break a block that was destroyed in the future, you’ll get a paradox. Paradoxes highly destabilize planet, so try not to create lots of them. Also, robot needs energy to move/jump/travel through time/craft/place blocks/mine blocks. Soon you will start running out of given energy. At this point you will need some generators. (currently, there are only 2 working generators: solar (place it with no blocks above) and heat (place it underground as deep as you can to get more energy).

After making this game I can say that the hardest part for me was GUI. This time I spent a lot of time on it, and it still looks awful. Also had no time for an sounds/music, so feel free to play your own music while playing my game 😀

http://www.ludumdare.com/compo/ludum-dare-30/?action=preview&uid=34143

Thanks for taking your time reading this post