Mindustry

This one requires quite a bit of luck, but you can increase your odds easily.
There is always an eclipse at the last wave of Nuclear Production Complex, if you've beaten it and there are still some enemy bases around it, just let the enemies recapture and you'll have another chance.

Tips

• To increase your chances, spam a few thorium and impact reactors away from your defense, eclipses are attracted to those and spam a TON of duos with either silicon or graphite. Personally I used silicon.
• Set up some spectre turrets with thorium and water, and hook them up with a processor and a switch in a way that they are disabled when you flick the switch, use this to damage the eclipse and switch it off when its close to death.
• Get a few force projectors and a lot of mender projectors. The eclipse will chow down your defenses FAST so rebuilding them and repairing will be very important. Polies and Megas also help but make sure to remove them when the boss is close to death
• Try to not use plastanium walls or any other damaging wall, plastanium is very good against it because it'll reflect the lasers but it will also make it harder due to having one more thing attacking it, for me, i put a small line at the front to make sure it wouldnt destroy everything while i spammed thorium walls and force projectors behind it.
• Keep rebuilding the reactors to keep its agro there, duos have short range so having it move is bad.
• You can use parallaxes to keep it in place, but make sure to have the same set up as the spectres