Diamond/coin strategy: Keep replaying the first boss, you will get 400 coins/completion. Use ~2 bombs and spam sword for the first few times. Then, go to the diamond trader in Snowvania to trade coins->diamonds. To speed up the process, spend your diamonds on bombsx2 to speed up the process and save coins.
How to complete Override (the hardest level for me):
1. Place control centers in the top, middle, and bottom left.
2. Create a network of collectors all around the map from the left to the middle.
3. Create 3 mortars for each creeper chamber. Create pulse cannons for security (optional)
4. From your collectors in the middle, create a few beams and 3 pulse cannons in each division.
5. Slowly progress towards the creeper: I like to put a shield in the rings left behind to get VIP access to the emitters/spore towers.
◾Just Made It: End a level with 5% armor and shield remaining, 1,200,000 Gold
◾Titan: Create a ship with over 5000 armor, 1,500,000 Gold (easily gotten by transforming into Guardian of Mana with an armor-boosting equipment, but it's also been proven possible by buffing the Pseudo-Epic to the max.)
◾Sniper: Finish a level with over 95% accuracy, 1,000,000 Gold
◾Badge of Conquest: Complete 15 missions, 1,000,000 Gold
◾Full Capacity: Acquire all skills, 2,000,000 Gold
◾O.C.D.: Own everything in the three shops, 2,500,000 Gold (by "three shops" it means the three equipment shops)
◾Perfectionist Elite: Finish a level with 4 Perfects beyond Level 16, 3,000,000 Gold
◾Ultimate Defender of the Enigmata: Defeat 10,000 enemies, 1,000,000 Gold
◾Warlord: Heartlessly defeat 2000 enemies, 200,000 Gold (forget the word "heartlessly")
◾Mega-Insanity: Crash into a boss 15 times, 100,000 Gold (you must crash 15 times in a single boss fight for this to count)
◾The Box of Doom: Collect an exploding box, 140,000 Gold
◾Filthy Rich: Obtain 5 million gold, 300,000 Gold
◾Strange Irony: Destroy Neko's Shop, 430,000 Gold (easier to get with the shop's boss form, but destroying the shop's "shop form" has also been proven possible)
◾Obliviator: Defeat over 95% of enemies in a level past Level 10, 400,000 Gold
◾Non-Random Achievement: Just kidding, it is random, 800,000 Gold (this achievement is 100% based on luck)
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They fly, right? They're ugly and hairy, right? C'mon, this is taking all day!