Hello and welcome to this guide!

So, generally my guides are longer and more detailed than this one. But since we only have 4 achievements, I will keep this guide brief.

You need to finish the game twice in 2 different difficulties, without using the missiles.

Finishing each difficulty has one achievement each, and finishing without missiles for each difficulty has one achievement each.

Finishing Veteran directly doesn't give the Rookie achievement, that's why 2 playthroughs are required.

When you finish a playthrough without a missile usage, you get both of the achievements for that difficulty, so at least we have that.

Hardest part of the playthroughs is to not misclick on your missiles. For this, go to Options > Control and make missile control button middle click button, instead of right button. I've lost a playthrough to misclick after %80 completion of that playthrough, so don't be like that, change the controls.

Also to note, you can change the difficulty from Options > Gameplay.

Generally the game isn't that hard, but if you are having a hard time, just get one type of weapon and don't change it. Each upgrade and same type of weapon gift box increases the firepower. I personally like the green weapon, and feel like the red weapon is not that good, but don't have data to support these feelings and the decision is yours anyways.

There are other simpler tips I can add, like make sure to not get hit by eggs, don't get too close to the edges etc. But I am skipping those.

Another useful tip: You can use an autoclicker if you don't want to click all the time. (Make sure you download these apps from trusted sources though. If you are fancy, you can even write your own autoclicker using AutoHotkey.)

And achievements pop when you quit the game, not when you finish the playthrough.

All in all, should be an easy 100. Thanks for reading probably my shortest guide.