Pretty fun game, been playing it for about two weeks. It's pretty simple, all you do is attack mobs for exp/credits. It has no energy requirements, you can click as much as you want every day.
There's an 8x exp/credit event going on atm, so starting now would be wise. You also gain 8x levels per level up (meaning you gain 8 levels every time you level up once).

Now is also a good time to find some cash credits/shard dusts which can only be found during event days such as this. Cash credits are used to upgrade your experience bonus (+x% exp from mobs), credits bonus (+x% credits from mobs) or skill bonus (+x% chance to gain a skill while attacking)

Shard Dust is used to buy items from the Dust Keeper. He sells various items that can be found in the Item Mall(item mall costs real cash) but for Shard Dusts.

Another way to find CC (Cash Credits) or SD (Shard Dust), is to kill beasts that randomly spawn and are relatively easy to kill once you get a little higher level and skills. And I guess that's all I can think of right now try it out!

Here's my referral link: www.immoralattack.com/referral.php?ref=2812
And for the non-referral: www.immoral-attack.com

My IGN is Jesus, just PM me or ask in the chat if you have any questions. Also, I suggest clicking your own referral link when you start out. It gives you 1,000,000,000 gold so you can buy some of the best gear to start out with (1,000,000,000 isn't much at all in this game btw.). And before you think "Omg, lol. One of these games where you have to buy shit to be good". Not true. I haven't spent a dime on this game so far and I have about the same stuff that someone who would pay would have.